The Disappearance of Laci Peterson:
Why Her Husband, Even If Innocent, Should Not Agree To A Lie Detector Test

By JONNA M. SPILBOR

Monday, Mar. 03, 2003

In recent weeks, news shows have frequently turned to the notorious case of Laci Peterson - the pregnant Modesto woman who disappeared on Christmas Eve from the home she shared with her husband, Scott. While watching one such bulletin, I turned to my own husband, and said, "Honey, promise me something. If I ever go missing without a trace, and the police are breathing down your neck, do not, I repeat, do not, take a lie detector test. Okay?"

On the advice of counsel, he agreed. Sometimes it helps to be married to a lawyer - even if you are subject to cross-examination for not taking out the garbage.

It's not as clear that Scott Peterson will follow the same advice. Thus far, he's done a lot of talking; indeed, he's even confessed to having carried on an adulterous affair just weeks before his wife's disappearance. A few stretches and pulls by police, and a morsel like this becomes a possible motive. Still, Scott Peterson has yet to hire counsel.

Now Peterson is being pressured to take a polygraph. So far, he's refused. But authorities are continuing to lean on him, arguing that he is not "cooperating." He should keep on refusing - even if he's entirely innocent.

Scott Petersen Is Plainly A Suspect In the Minds of the Police

Police and prosecutors have refused to call him a suspect. But they may be withholding the word simply in an attempt to avoid its legal consequences.

Place the word "suspect" before Scott Peterson's name, and arguably, a casual police visit transforms into a formal "detention." A seemingly impromptu chat session becomes an "interrogation." And the Fifth Amendment pops up as an obstacle to the police's investigation. Simply put, a suspect - unlike a husband - has an absolute right to remain silent.

Whether or not the police call Peterson a suspect, they certainly have treated him like one. The police conducted an investigatory search of the Petersons' home - and then they conducted another. This time, authorities pulled out everything that wasn't nailed down.

The first search might have been standard procedure. The second indicated that suspicion has likely fallen on Scott Peterson.

Although investigators have been tight-lipped about what they're hoping to find, they brought along Laci Peterson's sister to assist in the second search. By doing so, police have run the risk of contaminating a potential crime scene; a move which certainly will draw objections from defense counsel when - and if - evidence from the second search of the Peterson home is admitted in the matter.

Only Suspects Are Generally Given Polygraphs in the First Place

Furthermore, the search isn't the only evidence Peterson is a suspect. There's also the request for a polygraph (better known as a lie detector) itself.

The police may be telling Peterson they want to give him the test to "rule him out." If so, that's, quite frankly, a lie on their part.

Police typically reserve polygraphs for weak cases only. The reason is simple: when there exists strong evidence against an accused, a polygraph is wholly unnecessary. Ergo, lie detector tests are not used to rule someone out - but to rule someone very much in.

Polygraphs Are Often Inaccurate, and Provide Evidence Against the Innocent

Think of a polygraph as a sort of magician's hat, and a suspect as a brightly colored hanky. Any magician, even a bad one, can put a hanky into a hat and pull out a live rabbit. By the same token, police can put a mere suspect into a room with a polygraph machine, and pull out a full-fledged defendant. It's that easy.

With no other leads, the police are doing what they are prone to do: Working backwards. Instead of searching for clues to the killer, the cops are looking for reasons to convict Scott Peterson. In sophisticated legalese, this is what we fancy mouthpieces call a "fishing expedition." And it is precisely why Scott Peterson should keep his mouth shut.

Notice, in my analogy with the hanky, the magician and the rabbit, that I didn't say the suspect had to be guilty in order to become a defendant. That's because he doesn't: The magician's hat works every time.

Rarely do suspects pass polygraph tests. It doesn't mean all suspects are guilty. It means that lie detectors are often wrong.

What About Talking to the Police, But Not Taking a Polygraph?

Okay, you say, I can see why Peterson shouldn't take a polygraph - it might wrongly indicate that he's guilty. But why can't he talk to the police? If he's innocent, he's got nothing to fear, right?

Wrong. When the police tell you anything you say can be used against you, they mean it. Remember, under our system, only guilt - not innocence - needs to be proved. Scott Peterson doesn't have to "prove his innocence" by talking. Instead, the presumption of innocence means that, if he didn't do it, he doesn't need to talk.

If Peterson talks, he may inadvertently get himself into trouble - for instance, by giving slightly different accounts on different occasions due to a failure of memory. He may also attract more and more police attention - and distract from other leads.

Police have yet to speak to the witness, claiming they haven't had time to return the more than 8,000 phone tips they've received on the case. They have had time, mind you, to keep a close eye on Scott Peterson despite his continued protestations of innocence.

Maybe the most important piece of evidence the police have overlooked is the family dog Laci was walking when she disappeared. Although Laci never returned home from that walk, the dog did. Which means the pooch didn't get too far before his owner went missing. My advice to the Modesto police? Stop looking in the ponds, puddles and potholes, and start knocking on the neighbors' doors.

In the meantime, Scott Peterson should keep his eyes open, and his mouth shut. While communication may keep a marriage together, when one spouse goes missing, silence is golden.


Jonna M. Spilbor is a frequent guest commentator on Court-TV and other television news networks, where she has covered many of the nation's high-profile criminal trials. In the courtroom, she has handled hundreds of cases as a criminal defense attorney, and also served in the San Diego City Attorney's Office, Criminal Division, and the Office of the United States Attorney in the Drug Task Force and Appellate units. In 1998, she earned certification as a Court Appointed Special Advocate with the San Diego Juvenile Court. She is a graduate of Thomas Jefferson School of Law, where she was a member of the Law Review.

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