Does strangulation leave evidence?

It's indisputable that not a speck of trace evidence was discovered in the Peterson residence at 523 N.  Covena.  The detectives were faced with that reality as test after test on items seized and sent to the Ripon lab came back negative.  Nor was there any evidence of a struggle on Scott's body.  Detectives then reasoned that he drugged Laci to incapacitate her, then strangled her or choked her.  They had to drop the drugged element because their efforts to find evidence that Scott had possession of any drug that would incapacitate Laci were likewise futile.

So this is what Distaso ended up arguing:

It's very simple. The defendant strangled or smothered Laci Peterson the night of February, January, December 23rd, or in the morning while she was getting dressed on the 24th. I can't tell you when he did it. I can't tell you if he did it at night. I can't tell you if he did it in the morning. I'm not going to try to convince you of something that I can't prove. I don't have to prove that to you. I only have to prove that he did it.

What did the doctor tell us about strangling and smothering? It's not going leave a bunch of evidence. Remember this whole, went through all of this evidence. Where's the bloody crime scene? Remember what the doctor said? As crude as this sounds, and I hate to say it: If you don't put another hole in somebody, not going to get a big, bloody crime scene. It's just not going to happen.

Of course,  "a bunch of evidence" and "a big, bloody crime scene" grossly distorts reality -- not a speck of trace evidence was found in that home.

We also heard from Dr. Cyril Wecht that one of the reasons he didn't testify is because he would have had to admit that strangulation can be committed without leaving any evidence.

That's not what a strangulation study conducted by the San Diego District Attorney's office concluded.

The initial study consisted of 100 strangulation cases, which were selected at random from police reports submitted over a five-year period. The first 100 victims were all women who reported being choked by their partners with bare hands, arms, or objects such as electrical cords, belts, rope, bras, or bathing suits. In one case, a victim reported that her boyfriend put a plastic bag over her head and tried to suffocate her.

The purpose of the study was to improve the investigation and prosecution of strangulation cases in the county.

The general clinical sequence of a victim who is being strangled is one of severe pain, followed by unconsciousness, followed by brain death. The victim will lose consciousness by any one or all of the following: blocking of the carotid arteries (depriving the brain of oxygen), blocking of the jugular veins (preventing deoxygenated blood from exiting the brain), and closing off the airway, causing the victim to be unable to breathe.

Only eleven pounds of pressure placed on both carotid arteries for ten seconds is necessary to cause unconsciousness.4 However, if pressure is released immediately, consciousness will be regained within ten seconds.

To completely close off the trachea, three times as much pressure (33 lbs.) is required. Brain death will occur in 4 to 5 minutes, if strangulation persists.

One of the study's observations is that the offender is likely to have more evidence on his body than the victim will have on hers.

Because victims fear for their lives, they may protect themselves by trying to get perpetrators to release their holds by either pushing them back, biting them, scratching their faces, or pulling their hair.

Depending on the method of strangulation being used, the suspect may be the only individual with visible injuries.

For example, if the suspect is strangling the victim from behind and using a chokehold, the victim may protect herself by biting the suspect in the arm.

If the suspect is manually strangling the victim from the front (face to face), she may either push him away, scratch him, or pull his hair.

When officers arrive at the scene, they may find the suspect with visible injuries . . .

Of course, Scott had no such injuries on his body.

Strangulation has a good deal of potential to unwittingly leave forensic evidence at the crime scene.

Objective signs noted in strangulation victims include involuntary urination and defecation.  Miscarriages have been anecdotally reported occurring hours to days later.

And that involuntary urination and defecation is from the women that survive an attempted strangulation -- the possibility from pregnant women that die from the strangulation most assuredly would increase.

Of course, the MPD looked for evidence of involuntary urination and defecation because they sorely wanted to prove Laci was murdered in the home -- but they didn't find any.

So they created the myth that strangulation wouldn't leave any such evidence.  And Distaso distorted reality with his "bunch of evidence" and "a big, bloody crime scene" statement in his Closing Argument.