Circumstantial Evidence: The Scott Peterson Trial

When the Facts Cannot Be Proven Directly

Scott Peterson
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The trial of Scott Peterson for the murders of his wife Laci and their unborn child Conner is a classic example of a prosecution based almost solely on circumstantial evidence, rather than direct evidence.

Circumstantial evidence is evidence which may allow a judge or jury to deduce a certain fact from other facts which can be proven. In some cases, there can be some evidence that can not be proven directly, such as with an eye-witness.

In these cases, the prosecution will attempt to provide evidence of the circumstances from which the jury can logically deduct, or reasonably infer, the fact that cannot be proven directly. The prosecutor believes the fact can be proven by the evidence of the circumstances or "circumstantial" evidence.

In other words, in these cases, it is up to the prosecutors to show through a set of circumstances that their theory of what took place is the only logical deduction -- that the circumstances can be explained by no other theory.

Conversely, in circumstantial evidence cases, it is the job of the defense to show that the same circumstances could be explained by an alternative theory. In order to avoid a conviction, all a defense attorney has to do is put enough doubt into one juror's mind that the prosecution's explanation of the circumstances is flawed.

No Direct Evidence in Peterson Case

In the Scott Peterson trial, there was very little, if any, direct evidence connecting Peterson to the murder of his wife and unborn child. Therefore, the prosecution was attempting to show that the circumstances surrounding her death and the disposal of her body could be linked to only her husband.

But defense attorney Mark Geragos apparently made great progress in shooting down or offering other explanations for the same evidence. For example, in the sixth week of the trial, Geragos was able to debunk two key pieces of evidence that supported the prosecution theory that the fertilizer salesman dumped his wife's body in San Francisco Bay.

The two pieces of evidence were homemade anchors Peterson allegedly used to sink the body of his wife and a hair from his boat that was consistent with her DNA. Under cross-examination, Geragos was able to get police investigator Henry "Dodge" Hendee to acknowledged to jurors that the prosecution's own expert witness had determined that a water pitcher found in Scott's warehouse could not have been used to make a cement boat anchor found in his boat.

Alternative Theories for the Same Circumstances

Earlier, photos presented by Hendee and questions from prosecutors tried to give the jury the impression that Peterson had used the water pitcher to mold five boat anchors -- four of which were missing.

One of the few pieces of evidence the prosecution did have was a six-inch dark hair found on a pair of pliers in Peterson's boat. Geragos showed Hendee two police photos taken in the warehouse, one showing a camouflage jacket in a duffle bag and another, showing it resting inside the boat.

Under Geragos' questioning, Hendee said the hair and pliers were collected as evidence after a crime scene technician took the second photo (with the jacket in the boat). The line of questioning from Geragos strengthened the defense theory that the hair may have been transferred from Laci Peterson's head to her husband's coat to pliers in the boat without her ever being inside the boat.

As with all circumstantial evidence cases, as the Scott Peterson trial progressed, Geragos continued to offer alternative explanations for each piece of the prosecution's case, in hopes of placing a reasonable doubt in at least one juror's mind.

When Circumstantial Evidence Wins Over Direct Evidence

On November 12, 2004, a jury found Scott Peterson guilty of first-degree murder in the death of his wife Laci and of second-degree murder in the death of their unborn child Conner. He was sentenced to death by lethal injection the following year. He is currently on death row in San Quentin State Prison.

Three members of the jury spoke to reporters about what led them to convict Peterson.

"It was hard to narrow it down to one specific issue, there were so many, " said Steve Cardosi, the jury foreman. "Collaboratively, when you add it all up, it doesn't appear to be any other possibility." 

The jurors pointed to the deciding factors--

  • The bodies of Laci and their unborn child washed up close to where Peterson said he went fishing on the day that Laci was reported missing.
  • The fact that Peterson was a proven liar.
  • Peterson showed no remorse for the loss of Laci and their unborn child, including continuing his romantic conversations with his girlfriend, Amber Frey.

Mark Geragos did manage to offer alternative explanations for most of the circumstantial evidence that the prosecutions presented during the trial. However, there was little he could say that would reverse the lack of emotions that Peterson portrayed.