Evidence Assessment


This page records my overall assessment of the evidence in the case. For each element in the table below, I give an outline of my reasoning.
The likelihood ratio columns are how the evidence modifies my estimate of David Camm's guilt.
In common sense terms, ratios from 2 to 3 are "weak", 3 to 10 is "substantial", 10 to 30 is "strong", 30 to 100 is "very strong", more than 100 is "decisive".
Multiplying the numbers in each column, and then dividing gives an overall figure. Below the table I explain my reasoning for the probabilities given.

For evidence that I have discounted as having little or no value, please see Discounted Evidence.

Evidence
Prosecution
Evidence
Defence
Evidence
Interpretation
General likelihood of Camm being a killer

50
Very strong evidence for innocence
Forensics : blood spatter
2

Weak evidence for guilt
Forensics : gun shot residue and brass shavings

2
Weak evidence for innocence
Forensics : stain on David Camm's shoe
2

Weak evidence for guilt
David Camm's Alibi

20
Strong evidence for innocence
Boney's tale

5
Substantial evidence for innocence
Overall likelihood
4
10000
2500 = Decisive evidence for innocence

“Science is the belief in the ignorance of experts.”
Richard P. Feynman

General likelihood of Camm being a killer


Here I take into account the relative likelihood (ignoring other evidence) of Camm being a killer, given Charles Boney's history. The main point here is that Charles Boney had a history of violence to women. He has some kind of sexual fetish for shoes/women's legs, evidenced by earlier violent attacks on women. I will detail these attacks in more detail elsewhere, but the main attacks were:
(1) He violently attacked five young women, stealing shoes.
(2) He took young women hostage on three occasions, in two cases, he used a gun ( though no shots were fired ).

In the two incidents with guns, fortunately Boney was apprehended before he got very far, so we don't know how these attacks would have developed if had not been stopped.

There is also a clear progression of violence. All these previous attacks were essentially at random.
Thus it can be of no surprise whatsoever that Charles Boney would attack David Camm's family "out of the blue", his criminal profile is typical of a developing violent killer.
The removal of Kim Camm's trousers, and her shoes being placed on top of the vehicle at the crime scene, are consistent only with Boney's sexual fetish.

There are also various hard to understand aspects of the prosecution case. Why would Camm approach such an unreliable person as Boney? How did Camm meet Boney on the day of the murder? If Camm is guilty, why did he allow Boney's sweatshirt to be found at the crime scene ( if he plotted with Boney, it would be very dangerous for Boney to be caught, with a high risk of Boney implicating him ). Why choose such a risky alibi - if any of the 10 other people at the gym noticed he had gone, he would immediately come under great suspicion.

In contrast, it's very unusual for a husband to attack and murder not only his wife, but also his children. However, David Camm had been unfaithful to his wife, and I take account of this ( although since infidelity is very common, estimated at 30%-60% in all marriages, this has to be a rather minor adjustment ).

So I take this as very strong evidence of innocence.

Note that before Charles Boney's presence at the murder was proven, this would be much reduced, since the mere unexplained fact of the murder would cast considerable suspicion on David Camm - a priori, one might guess the chance of him being the murderer as 1 in ten. But once Boney is identified, the overwhelming improbability of David Camm being a father able to murder his family for no discernible reason comes fully into play.

I take Boney's active presence as proven beyond reasonable doubt by his fresh handprint on the vehicle, his sweatshirt, the injuries to Kim Camm, the removal of Kim Camm's clothing, the discovery of the DNA of Kim on his sweatshirt, the gun shot residue found on his sweatshirt, and by his inability to give a plausible account of this evidence.

General remarks about the forensic results

The forensic evidence against David Camm consists of alleged blood spatter ( 4-8 tiny specs of blood found on his shirt ), a blood stain on his shoe, a spec of brain matter found on his shirt and two particles of gunshot residue.
I do not have a strong view on this evidence, but overall I find it ambiguous - he could be innocent, and this matter got on to his clothing when he discovered the murder. If he is guilty, and fired the shots in close proximity to the victims, you might expect there to be a larger quantity of material - more gun shot residue, more high-impact velocity spatter, more brain material, than was found. I am by no means convinced by the prosecution arguments that innocent explanations can be ruled out with any certainty. At best, this evidence supports some level of suspicion.

A major problem is that we simply do not have access to the evidence - therefore my conclusions are based on almost zero data. But there have been allegations that I find highly credible that the investigation was amateurish, and the prosecution blood stain experts should be regarded as potentially "liars for hire". See Problems with the investigation.
Based on overall considerations, I expect that when the evidence is examined in detail, it will prove to be ambiguous or plain wrong.

Forensics : blood spatter

See Blood-spatter

Forensics : gun shot residue and brass shavings

See Brass-Shavings

Forensics : stain on David Camm's shoe

I feel this could easily result from David Camm's shoe making contact either with a wound on Kim Camm's body, or with pooled blood on the floor, as he entered or exited the vehicle.
I have not seen photographs of the stain. In view of the statements by prosecution experts, I accept it as weak evidence of guilt.

David Camm's Alibi
As far as I can see, David Camm had a strong alibi. There were multiple witnesses, including a witness who recalled talking to David Camm in the game that David sat out. And there was no reason for these witnesses to invent their statements - during the initial investigation, the time of the murder was placed after the games, it was only later than the prosecution alleged that David left the basketball session to commit the murder. I find the alibi to be strong. It is very hard to imagine how David could have left and his absence not be noticed by so many people.
See Alibi

Boney's tale

The issue here is why Charles Boney was unable to devise a plausible tale. If David Camm was the real shooter, and Charles Boney only played a minor role, Charles only had to tell the truth, and he would have a credible defence. But in fact his tale was an obvious pack of lies, his story of meeting David Camm was impossible to corroborate, and highly implausible. I conclude that in all likelihood the meetings never took place, and were an obvious invention by Charles Boney whose only means of avoiding a death penalty was to blame David Camm for the murder. ( To be explained in more detail later ).