There have been some great theories as to who committed this murder posted in this thread. I’ve been able to speak with people who worked for Mr. Percy, LE, family friends, family and neighbors (and some here who really know their stuff. You know who you are. Excellent work my friend.)
I agree, unless there’s enough proof to indict someone as having committed a given murder, there are lots of possibilities. That said, as you likely know, possibility and probability are different things entirely.
The three promising initial suspects in this case were Andrew Potash (boyfriend or former boyfriend of the victim at the time of the murder), Calvin Fentress III (reportedly dated the victim), and Tully Friedman (also reportedly dated the victim though this is not reported in any stories I have read. I have been told by someone in the know, however, that there’s a 90% chance that Friedman and Valerie dated. I have been told leads on Friedman were investigated “into the ground.” That indicates that he did indeed date her.)
Investigators do not agree on motive. One said he thinks Valerie was murdered by someone who knew her, knew where her room was and risked breaking in to kill her at home because she was virtually never alone in the months before the crime. He believes the motive was “revenge,” for something. Perhaps jealousy as she quite possibly had three young men in her orbit the summer before the murder (technically the murder was that summer. Those young men in her orbit may be why Percy campaign staffers interfered with the investigation. They, of course, should never have been able to do that and it did not help find the killer. None of the investigators think that interference was to cover up the crime. It was just bad local cops allowing control freak campaign workers to interfere. They had nothing else to do as the campaign was suspended for at least two weeks the day of the murder.) That summer (’66) the victim commuted to work with her brother most days (the later drove her to and from the city. Some days she came back on the train. Either way, she was nearly always if not always with someone. At least one fellow campaign worker lived at the end of the train line, too. He rode back with her the day before the murder. So it would have been hard to attack her daylight hours without witnesses. As a wealthy young woman living at home in a house where her father employed a chef and the chef’s wife, she didn’t have to go grocery shopping either. So without further adieu, the suspects:
Potash’s alibi checked out.
Friedman took a lie detector test. He passed. Judging from pictures, he also appears to be six feet four or six five, or as much as 8-9 inches taller than Mrs. Percy’s description of the killer. Friedman was described as tall and slim in news reports, which indicates that he was thin enough to easily get in and out of the door the killer entered and exited through. According to Dr. Hohf’s account and news stories it was partially blocked by a piano bench (Hohf estimated that the door could only be opened a foot to 14 inches wide.) In his account Hohf also recalls how dark it was that morning. 5 a.m. with overcast skies. I believe Mrs. Percy may have been able to give an accurate height description in the fleeting moment she saw the killer in a dark room, illuminated only by the killer’s flashlight. However, I do not think her 180 lb. weight description of the killer was accurate. Five eight, 180 lbs. is not skinny. Skinny was required to get through that door so fast as he ran out of the house, and may have been necessary to get into it. Either way, getting the weight correct under such circumstances seems like it would be more difficult.
Of course, there were other suspects, including members of the Malchow burglary gang. State cops suspected the killer was one of them because they think the person who broke into Fred Wacker Jr.’s mansion, 16 miles north of Percy's house in south Lake Bluff, in ’65 (Wacker’s place was actually broken into twice that year) was the Percy killer based on the unique method of cutting and breaking glass at both residences.
But at the time of the Percy murder and Wacker break-ins, Calvin Fentress lived just three minutes south (and on the same road, Greenbay) of Wacker’s house. So it just as easily could have been him. I'm not sure if investigators ever connected those two facts. They may have been so focused on the gang burglary motive because the gang had worked in the area prior to the murder. In ’66, Fentress was reportedly living Lake Forest, ostensibly at his parent’s house. (The Fentress and Wacker residences are still there, quite near each other though they are in different towns.)
Other information appears to make Fentress suspicious; a former Percy campaign worker said Fentress was around 5'10 or 11", or as close to two inches in height of Mrs. Percy’s description of the killer. The same source said Fentress was “very slim.” As such, he could have gotten in and out of the partially blocked door easily. I obtained this info first hand. As far as I know it has not been published before.
Fentress also did not pass a lie detector test and reportedly was highly nervous when taking it. (His results were said to be “inconclusive.”
After long careers in LE, two former detectives I spoke with both recalled cases where they knew of a guilty person who was able to pass a lie detector test but never a case in which an innocent person could not pass one.
The bloody glove that was found near the Percy’s home the morning of the murder was described by the Sun-Times as a type “ordinarily used by motorists.” To me this sounds like driving gloves. Such gloves are associated with the wealthy. Fentress was Lake Forest wealthy. His father was a former head of Allstate Insurance and lived on a huge estate. It made Percy’s place look like servant’s quarters.
At the time of the murder, Potash, Friedman and Fentress were all young men working on Percy’s campaign. One would think they were doing it not only to work but build their resumes for future careers in public service.
As such, a recent Google search of all three revealed photos and information on Friedman and Potash but virtually nothing on Fentress (he does appear, briefly, in one of his parent’s obits.) If it wasn’t for all of the above, I’d say this was only a coincidence. But that is not the case.
There has been so much written about this case. Some of it is clearly inaccurate. Some info that came out a week after the murder I think was disinformation planted by cops who thought they’d revealed too much to the press. And they had. That said, I find the following makes Fentress suspicious in the Percy murder:
His height is a close match to Mrs. Percy’s description.
He was very skinny. So he could get into and out of the partially-blocked door easily.
He did not pass a lie detector test.
The test made him “very nervous.”
He lived three three minutes from the Wacker house, and on the same road, when the break-ins occurred there the prior year.
His demographic fits the type of glove (likely a driving glove but possibly a dress glove) left at the scene, which was linked to the murder via blood and fiber evidence.
Google searches turn up nothing on him whereas the reveal info and pictures on the other suspect and former suspects.
And, of course, he dated the victim.