4 Univ of Idaho Students Murdered - Bryan Kohberger Arrested - Moscow # 75

[iamshadow21]

Excuse me if I'm wrong or missed something, but didn't Ethin's twin enter the house? He arrived before police? and went in to check ? Maybe he left a shoe-print prior to realizing the severity of the situation? jmo imoo

If he had, in my opinion LE would have known this due to a) asking him where he'd been in the house and what he'd done and b) taking his shoes for the process of elimination.

Any prints in blood he left would have been in blood that was clotted, separated (red cells from serum/plasma), and in the process of drying. This would be obviously different to investigators from prints left in fresh blood, presumably by the perpetrator.

Blood goes through a known and measurable series of changes after it is shed. I posted a link to a scientific article about pooled blood further up the thread. Here's one about drying times of smaller amounts of blood. Both articles I have linked today used hard surfaces - the Moscow house was floored throughout in modern lino.

Drying properties of bloodstains on common indoor surfaces

MOO

 

[iamshadow21]

And, have another, in plainer language, and without a paywall.

How Bloodstain Pattern Analysis Works

The article is broad and goes over several pages, but this is the bit in question relevant:

Patterns of drying help analysts determine how long an assault went on, detect whether it took place all at once or in stages, and nail down possible crime scene contamination [source: Wonder]. Clotting patterns in blood provide similar information and can help nail down the time factor if analysts arrive at the scene before blood can dry. Clotting generally begins within three to 15 minutes, although actual times vary by the amount of blood, surface type and environment.

Tl;dr, for a print to be left in fresh blood without signs of clotting, it would likely have had to have been left very shortly after the blood was shed. Minutes after the murders, not hours. And they can determine possible crime scene contamination using patterns of drying.

There is a source list at the end of the article.

MOO

 

[jepop]

And, have another, in plainer language, and without a paywall.

How Bloodstain Pattern Analysis Works

The article is broad and goes over several pages, but this is the bit in question relevant:

Patterns of drying help analysts determine how long an assault went on, detect whether it took place all at once or in stages, and nail down possible crime scene contamination [source: Wonder]. Clotting patterns in blood provide similar information and can help nail down the time factor if analysts arrive at the scene before blood can dry. Clotting generally begins within three to 15 minutes, although actual times vary by the amount of blood, surface type and environment.

Tl;dr, for a print to be left in fresh blood without signs of clotting, it would likely have had to have been left very shortly after the blood was shed. Minutes after the murders, not hours. And they can determine possible crime scene contamination using patterns of drying.

There is a source list at the end of the article.

MOO

Just wanted to post thanks as always for your measured and well researched posts, and especially all your work!. I've learnt much about physical/biological evidence and methods of assessment.

 

[iamshadow21]

Just wanted to post thanks as always for your measured and well researched posts, and especially all your work!. I've learnt much about physical/biological evidence and methods of assessment.

A lot of Googling and a special interest, that's all. I try to find as much that's plain language and accessible to everybody as I can. I'm learning with every article I find, and I'm happy if me sharing something means someone else learns something they find cool, too.

MOO

 

[Cool Cats]

Excuse me if I'm wrong or missed something, but didn't Ethin's twin enter the house? He arrived before police? and went in to check ? Maybe he left a shoe-print prior to realizing the severity of the situation? jmo imoo

Yes, there were people there who discovered the 2 crime scenes but then police came and secured the scenes keeping people from going in the house.

After 8 hours alot of the blood would be dry already and most witnesses have enough sense not to step in blood they see pooling on the floor, dry or not.

People who discover crime scenes before police arrive are considered witnesses and if any of them did leave a footprint (dried blood) then forensics would do their analysis to eliminate these additional footprints. When securing crime scenes Detectives have protocols for ruling what evidence is part of the crime scene.

LE will ask if they can take the witnesse's shoes and collect their DNA. If the person refuses they will get a person search warrant. I don't know if they did this at the Moscow crime scene.

Idaho murders: Crime scene photo shows eerie handprint on glass window next to evidence tape

Authorities haven't released the crime scene as yet, after announcing on Friday, December 2, that private security was hired to monitor the house

meaww.com

According to the former detective, investigators likely put the red tape on anything where potential evidence may exist. "When they are scrubbing a crime scene, they will put evidentiary tape wherever they believe that there is evidence that exists and they will be the ones collecting that evidence. They'll try to rule it in or rule it out as being part of the crime scene," Williams explained.

 

[BeginnerSleuther]

“For example, wet or moist evidence that is packaged in plastic will provide a growth environment for bacteria, which can destroy DNA evidence.”

From this link

Understanding DNA Evidence: A Guide for Victim Service Providers

I’m no expert but read a bit after seeing that theory posted. BK may have thought he was destroying his dna. I just wonder what was in those bags to cause him to go to all that trouble? Perhaps it wasn’t his dna he was hiding? Perhaps it’s some sort of OCD. I have no clue, but putting it in the neighbor’s trash leads me to believe he was trying to hide something. JMO

People with eating disorders and those with OCD do this often. To know it's suspicious, we'd have to know if he did these things before the murder.

 

[Nila Aella]

And I've posted links on how valuable and rarely wrong the simple technique of swabbing touch DNA on a use point is.

So we have links on both sides and I imagine people are tired reading them. Just my opinion.

IMO. When it's single source, I'd like to see links (from juried publications) that question it.

TIA.

Most research is done on mixed samples, but some include single source data. I saw this one cited in both peer reviewed articles and non peer reviewed articles discussing transfer dna that includes single source. The research itself is peer reviewed (2015) I linked the research data policy. In my brief search: Many of the later articles on the subject are paywalled or require requests to get the full text of the research. MOO

In 85% of cases, the DNA of the other person was transferred to the knife and profiled. In one-fifth of the samples, the DNA analysis identified this other person as the main or only contributor of DNA to the 'weapon'

Forensic DNA evidence is not infallible - Nature

As DNA analysis techniques become more sensitive, we must be careful to reassess the probabilities of error, argues Cynthia M. Cale.

www.nature.com

Research data policy | Authors | Springer Nature

At Springer Nature we want to enable all of our authors and journals to publish the best research, which includes achieving community best practices in the sharing and archiving of research data - Springer Nature Research Data Support enables researchers to do this quickly and securely.

www.springernature.com

Anyone have any idea what the "organizing trash into separate zip loc baggies" means?

Honestly, I am surprised by the response to putting trash into ziplock baggies. I know people that do this with certain types of food (especially veggies/leafy/stinky leftovers/grease) to prevent their garbage from stinking. Especially rurally, where garbage pickup is not twice a week. People do not want stinking garbage or dangerous animals visiting their property looking for food. IMO it is going to depend on WHAT he was putting into baggies. MOO

And the fact that he put garbage into a neighbors bin. They could still get his dna there and it was in a location near him (as opposed to him distancing himself further from it). I once had a neighbor that would take his garbage to the park can. At first I thought, what is he trying to hide? Paranoid? Then I realized he generated such a small amount of garbage that it would take him six weeks to fill a full receptacle. One tiny bag, every week, to the park's can. MOO

 

[Nila Aella]

I ran into this article this morning. Heavy reading, but interesting. DNA Evidence in the Legal System (National Library of Medicine. (1996)

National Center for Biotechnology Information

www.ncbi.nlm.nih.gov

edit: added date

 

[CSIDreamer]

I must have purchased a dozen pair of Vans when my son was a teen and even a preteen. It was the only brand he'd wear but he is now 34. So I can see why they are now considered 'for older people.' I think he does occasionally wear them still because he says they are very comfy for wide feet.

Oh, goodness. I buy Vans for my toddler grandchildren. They come in all sizes.

 

[Montecore1]

Apparently, it causes dna to degrade faster.

Correct...lots of proof online that DNA degrades faster in plastic bags, I posted a few awhile back but here are a couple more.

https://vfl.vermont.gov/sites/pslab/files/documents/EVIDENCE%20Packaging%20Power%20Point%20201109%20pdf.pdf

https://www.ojp.gov/pdffiles1/nij/bc000657.pdf

 

[Knitty]

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