Science is our best witness in this case. Science is not biased and it does not lie. -Sheriff Bill Gore, SDCSD press conference, September 2, 2011 That statement makes for a nice sound bite and is undoubtedly meant to impress the uninitiated and the uninformed in criminal investigation. What is true is the following: Science CAN be our best witness but ALL evidence must be evaluated within the larger case context in order to determine relevance and weight. Science CAN be unbiased and not lie, but both bias and spin may be attached to it by those involved in its evaluation and interpretation. One of the best examples that I know of to support what Ive said above is from a study involving DNA evidence: We took a mixed sample of DNA evidence from an actual crime scene- a gang rape committed in Georgia, US- which helped to convict a man called Kerry Robinson, who is currently in prison. We presented it, and Robinson's DNA profile, to 17 experienced analysts working in the same accredited government lab in the US, without any contextual information that might bias their judgment. In the original case, two analysts from the Georgia Bureau of Investigation concluded that Robinson "could not be excluded" from the crime scene sample, based on his DNA profile. (A second man convicted of the same crime also testified that Robinson was an assailant, in return for a lesser jail term.) Each of our 17 analysts independently examined the profiles from the DNA mixture, the victim's profile and those of two other suspects and was asked to judge whether the suspects' profiles could be "excluded", "cannot be excluded" or whether the results were "inconclusive". If DNA analysis were totally objective, then all 17 analysts should reach the same conclusion. However, we found that just one agreed with the original judgement that Robinson "cannot be excluded". Four analysts said the evidence was inconclusive and 12 said he could be excluded. http://www.newscientist.com/article...-dna-evidence-can-mean-prison-or-freedom.html The only scientific evidence that points to any significant degree toward the RZ case being a suicide relates to the relative absence of unidentified DNA and fingerprints and the presence of RZs DNA and fingerprints in incriminating locations. (Although, we do know that there was low level unidentified DNA found In mixed samples from RZs fingernails as well as from the rope used in the hanging; a large knife used to the cut the rope; the bed frame to which the rope was tied; a door knob on the balcony door; and a pair of black gloves found on a table in the mansion.) However, I would hardly suspect that in this day and age of CSI programming that people involved in murder would not take reasonable precautions against leaving significant biological evidence behind. Similarly, I think it unlikely that someone would not be able to readily think of ways to leave behind biological evidence and fingerprints from the victim in order to stage the scene. I dont believe that in most cases including this one that it does much good to look at individual elements in isolation. Similarly, a look at the science alone does not give an accurate portrait of what may have happened. For Sheriff Gore, the science that he speaks of in such glowing terms are cherry-picked elements loosely stitched together in order to force the evidence to fit the theory. Unfortunately he does not address the numerous elements that point to murder. Just as taking things out of context in an interview can paint a false picture, so too, taking evidence out of context and piecing it together can paint a false picture. Therefore, only after a thorough examination of the known facts surrounding a case, and a multidisciplinary forensic investigation, should conclusions be drawn." -William C. Thompson, Department of Criminology, Law & Society, University of California To illustrate the danger of out-of-context evidence, I would like to present the following true case in which science plays a starring role, primarily in the form of DNA evidence. (My apologies in advance for the length, but this is the best illustration Ive ever seen with regard to what Ive been discussing so far.) The Alan and Diane Johnson murder investigation. A gunman is preparing to murder a couple in their home. He finds the ammo box and retrieves some ammunition. After loading a rifle he tinkers a bit with the scope and heads out. To ensure that he wont leave DNA, or fingerprints at the scene, he puts on latex gloves and leather gloves over top. Moments prior to shooting his intended victims, he spots a bathrobe and puts it over his clothes to reduce the possibility of blood spatter on his clothing. Two shots are fired, two people are dead. In the ensuing investigation, police find the following. Matching male DNA: On the barrel of the murder weapon. On the scope of the murder weapon. On one of the spent cartridges found at the crime scene. On the insert of a box of ammunition for the murder weapon. On the inside of a latex glove found in the garbage outside.* On the inside of a leather glove found in the garbage outside.* On the collar of a bathrobe.* (*Evidence including blood spatter and gunshot residue linked the bathrobe and gloves to the murders.) All of the DNA profiles belonging to this intruder, were partial, weak profiles. Matching fingerprints: On the scope of the murder weapon. On one of the spent cartridges found at the crime scene. On the insert of a box of ammunition for the murder weapon. In summary, 7 matching male DNA profiles were found in highly incriminating locations as well as matching fingerprints in 3 locations. That is a LOT of physical evidence pointing in one direction. Whoever was the donor of this DNA is the shooter, right? If the donor was not the shooter, they would, at the very least, be involved, right? If, for some inconceivable reason, this is DNA that is completely unrelated to the crime, surely it would prevent a successful prosecution of the real perpetrator, right? The totality of the evidence must be the arbiter in evaluating the relevance of a particular piece of evidence. With this in mind, consider the DNA evidence that Ive presented in this example. As Ive indicated, 7 matching instances of DNA found in or on incriminating places or things further corroborated by fingerprint evidence seems overwhelming. There is quite a bit that I havent revealed. For example, there is more DNA, but its from a female. On the inside of a right-handed latex glove found in the garbage outside. On the inside of a left-handed leather glove found in the garbage outside. On the pink bathrobe. On hair taken from the .264-caliber rifle used to shoot the Johnsons The profile from the inside of the gloves was not a partial profile, (as was the case with the male profile,) it was a complete profile. Whos the shooter? There are two possibilities as to the meaning of the DNA that Ive presented. There is a male shooter and the DNA pointing to a female is simply irrelevant, DNA for which there must be an innocent explanation. There is a female shooter and the DNA pointing to a male is simply irrelevant, DNA for which there must be an innocent explanation. DNA that is relevant to this or any case will dovetail into the rest of the evidence and fit. Case context determines DNA relevancy, DNA does not override case context (which, of course includes other forensic evidence,) and radically alter the clear direction of a case. Case context: Alan, 46, and Diane Johnson, 52, lived in an attractive home that sat on two acres of land in an affluent suburb in the small community of Bellevue, Idaho. They had been married for 20 years and were devoted to each other and to their two children, Matt and Sarah. The Johnsons were well liked in the community. Alan was the co-owner of a popular landscaping company and Sarah worked for a financial firm. In the early morning hours of September 2, 2003, Sarah Johnson ran out of her home, screaming for help. She told neighbors that her parents had just been murdered. When police arrived, they found Diane Johnson lying dead under the covers of her bed. Prosecutors would say at trial that the shooter placed the end of the rifle on her Dianes head and pulled the trigger, a gunshot blast that removed most of her head. Based on wet bloody footprints and blood spatter, it appeared that Dianes husband had stepped out of the shower and was then shot once through the chest from a distance of about three feet. Alan fell to the floor and then stood and walked toward the side of the bed where his wife usually slept. He then collapsed and was found lying next to the bed, having, ultimately, bled to death. The shower was running and Alans body was still wet when police arrived. The police immediately secured the crime scene including sectioning off an entire block around the house. In a trashcan outside of the Johnsons home investigators found a bloody pink bathrobe and two gloves a left-handed leather glove and a right-handed latex glove. Inside the home detectives found a trail of blood spatter, tissue, and bone fragments that went from the Johnsons bedroom, into the hall, and across to Sarah Johnsons bedroom. A .264 Winchester Magnum rifle was found in the master bedroom. Two butcher knives, wiped completely clean of fingerprints, which were strategically placed at the end of the Johnsons bed near the bodies of Alan and Diane Johnson. A magazine of bullets was also found in Sarahs bedroom, which was located around 20 feet across the hall from the Johnson's bedroom. There was no evidence of forced entry into the home. As investigators removed Alan and Diane's bodies from the house, noticed a coldness and distance from Sarah. (She sat on a nearby fence and with apparent indifference watched her parents come out in body bags.) When Sarah Johnson first talked to the police she said that she woke up around 6:15 a.m. and heard her parent's shower running. She continued to lie in bed, but then heard two gunshots. She ran to her parents bedroom and found that their door was closed. She did not open the door, but rather called for her mother who did not answer. Frightened, she ran out of the house and began screaming for help. Her story of what happened would change several times throughout the investigation. Sometimes she said her parents door was slightly opened and other times she said her door was closed, but not her parents door. Based on the forensic evidence found in the hall and in Sarahs bedroom, both her door and her parents door would have to have been opened during the gunshot blast that ended her mothers life. Sarah also admitted that the pink robe was hers, but denied knowing anything about how it ended up in the trash. When first asked about the robe, her first response was to say that she did not kill her parents, which investigators found odd. She said she thought the killer was a maid who had been recently fired by the Johnsons for stealing. The owner of the rifle used to kill the Johnsons belonged to Mel Speegle, who was renting a garage apartment in a guesthouse located on the Johnsons property. He was away over the Labor Day weekend and had not yet returned home on the day of the murders. When questioned, he said that he did not lock up his guns or ammunition, but hid them in his closet under piles of clothes. Sarah Johnson was described by neighbors and friends as a sweet girl who enjoyed playing volleyball. But another Sarah had emerged over the summer months, one that seemed infatuated and obsessed with her 19-year-old boyfriend, Bruno Santos Dominguez. Sarah and Dominguez had been dating for three months prior to the murder of her parents. The Johnsons did not approve of the relationship because Dominguez was 19 and an undocumented Mexican immigrant. He also had a reputation for being involved in drugs. Close friends of Sarahs said that a few days prior to the Johnsons murder, Sarah showed them a ring and told them that she and Dominguez were engaged. They also said that Sarah often lied so they did not completely buy into what Sarah was saying about her engagement. On August 29, Sarah told her parents that she was spending the night with friends, but instead she spent the night with Dominguez. When her parents found out, her father went to look for her the next day and found her with Bruno at his familys apartment. Sarah and her parents argued and she told them about her engagement. Diane was very upset and said that she was going to go to the authorities and report Dominguez for statutory rape. If nothing else, she hoped to have him deported. (Other than to prevent her parents from acting on these threats, there was evidence that the Sarah murdered her parents to get their money so that she and Santos could go away together. Ultimately, Sarah's boyfriend testified for the prosecution, primarily to show he had nothing to do with the murders and that Sarah had talked about hating her dad and spoke of shooting him because of his disapproval of the relationship.) They also grounded Sarah for the rest of the Labor Day weekend and took her car keys. During the following days, Sarah, who had a key to Speegles apartment, was in and out of the guesthouse for various reasons. Both Diane and Sarah called Matt Johnson, who was away at college, on the night before the murders. Matt said his mother cried about Sarah's relationship with Dominguez and expressed how embarrassed she felt by Sarah's actions. Uncharacteristically, Sarah seemed to accept her parent's punishment, and told Matt that she knew what they were up to. Matt did not like how the comment sounded and almost called his mother back, but decided not to because it was so late. The next day the Johnsons were dead. DNA testing showed that there was blood and tissue belonging to Diane on Sarahs pink robe, along with DNA that matched Sarah. Gunshot residue was found on the leather glove and Sarahs DNA was found inside of the latex glove. Dianes DNA was also found in blood that was on the socks Sarah was wearing on the morning her parents were killed. On October 29, 2003, Sarah Johnson was arrested and charged as an adult on two counts of first-degree murder to which she pleaded not guilty. During the trial there was a lot of testimony about Sarah Johnsons inappropriate behavior and lack of emotions about the brutal murder of her parents. Neighbors and friends who offered comfort to Sarah on the day her parents were killed said that she was more concerned about seeing her boyfriend. She also did not seem traumatized, which would be expected if a teen went through the experience that she had inside the house when her parents were gunned down. She had a manicure the day before the funeral, because she didn't want to chip her nails the next day. She told her manicurist that she wanted to get on with her life. At her parent's funeral she talked about wanting to go play volleyball that evening and any sadness that she displayed seemed superficial. Witnesses also testified about the troubled relationship between Sarah and her mother, but many also added that it was not that unusual for a girl her age to fight with their mother. However, her half-brother, Matt Johnson, gave some of the most insightful testimony about Sarah, although it also proved to be some of the most damaging. He described her as a drama queen and a good actor who had a propensity to lie. During part of his two-hour testimony, he said that the first thing Sarah told him when he arrived to their home after finding out his parents had been murdered, was that the police thought that she did it. He told her he thought Dominguez did it, which she vehemently denied. She said that Dominguez loved Alan Johnson like a father. Matt knew this was not true. She also told him that at 2 a.m. on the night before the murders, that someone had been to the house. Her parents checked the yard to make sure no one was out there before they went back to bed. She had not provided this information to the police. Regardless Matt did not believe her, but did not challenge what she was saying. In the weeks after the murders, Matt testified that he avoided asking his sister about the murders because he was afraid of what she might tell him. The testimony of cellmates of Sarah's who testified about some of the damaging comments she made regarding the murders was challenged. One cellmate said that Sarah said the knives were placed on the bed in order to throw off the police and make it look like a gang-related shooting. Sarah was fascinated with crime stories, and based upon that exposure from novels and from television; she likely would have understood evidence and how to get rid of it A summary of evidence against Sarah Johnson: Investigators needed to prove that Sarah wore the robe on the morning of the murders. To do that, they had to analyze the shirt she had on that day. On the day of the murders, Sarah Johnson was wearing a blue cotton t-shirt with green paint smeared onto it. Scientists took samples from the t-shirt and fibers from inside the bathrobe and used a scanning electron microscope to compare the similarities. They found paint on both the t-shirt and the bathrobe with the same chemical makeup. A shower cap, which may have been used to prevent biological evidence to deposit in her hair, was flushed down the toilet. Plumbers found it several weeks later when it clogged the drain. (Although it was strongly coincidental, there was no way to definitively tie it to the murders because, for obvious reasons, there was nothing of forensic value left.) There was a bruise on her shoulder, coincidentally, the day her parents were shot with a rifle In a photograph of Sarah, several linear bruises that were approximately between 2 and 4 inches long are clearly visible near the top of her left shoulder. Witnesses who testified in the trial could not confirm that the marks were from a gun, but there was evidence of some sort of struggle near the doorway to the bathroom where Alan Johnson was shot. Possibly, as Alan Johnson fell, he grabbed the gun from the shooter's hands" and pulled her into the door jam, which would have been in line with the her left shoulder? While on the topic of shoulders, at the time of the shooting, Sarah Johnson's shoulder was 51.5 inches from the ground. A prosecution expert testified early in the trial that, based on Alan Johnson's gunshot wound in his upper left chest, the exit wound on his upper left back and the bullet impact point in the back of the shower, the rifle would have been fired from 51.5 inches above the ground, yet another coincidence. If an unknown shooter committed this crime, it would appear that he was remarkably similar in physical stature. Matching DNA belonging to Sarah Johnson found on the following: On the inside of a right-handed latex glove found in the garbage outside. On the inside of a left-handed leather glove found in the garbage outside. (The matching right-handed leather glove was found in Sarahs bedroom) On the pink bathrobe. On hair taken from the .264-caliber rifle used to shoot the Johnsons. The profile from the inside of the gloves was not a partial profile, it was a complete profile. DNA from the parents found on the following: A live shell cartridge, in Sarahs bedroom with her mother's DNA on it. The bottom of the wool socks worn by Sarah the morning of the shootings matched her mother's DNA. On the back of the pink robe worn by the shooter there was a treasure trove of biological material, (this included high velocity blood spatter, bone fragments and human tissue.) DNA sampling from the blood spatter determined that it was from both parents. On the outside of the brown leather glove, Dianes DNA was found. If it was an intruder, the owner of the unknown matching DNA, the following would have to be true: There would be a conscious decision to take the life of two people, presumably without motive. He would go to the Johnson residence without a weapon. He would enter both the guest house and the main residence while leaving no signs of forced entry. While in the guest house, the intruder would happen upon the Winchester .264 Magnum rifle and ammunition, take them, and take nothing else. He would then enter the main residence, navigate through a dark unfamiliar house, ignore taking any objects of value, take the time to find latex and leather gloves to put on, spend more time to find a robe to slip into to prevent his clothes from getting messed up, decide to find a shower cap to prevent his hair from getting messed up, and then walk into the master bedroom to shoot Diane Johnson in the head at close range and a moment later shoot Alan Johnson exiting a shower in the bathroom. Having taken nothing of value, and leaving a potential witness in house (Sarah) completely unharmed; he would then flush the borrowed shower cap down the toilet, place two butcher knives at the foot of the Johnsons bed, leave his borrowed rifle in the master bedroom, exit the house, dispose of the borrowed robe and gloves in the Johnson's garbage can, and slips away into the darkness. Plausible? Hardly. Sarah Johnson had the means, motive and opportunity to commit the crime. Despite unexplained DNA evidence, the prosecutors had the confidence in their case to proceed, and thankfully the jurors werent swayed smoke and mirrors utilized be the defense. As this example has illustrated, unexplained physical evidence, whether it is DNA, fingerprints etc., that doesnt fit into the context of the case can and should be dismissed. The extraordinary sensitivity of DNA testing allows for the discovery of profiles completely unrelated to a crime.