The Odds


 

What are the odds against the state's assertion that all of these coincidences and occurrences were possible and likely?

 

In 1718 De Moivre pioneered the development of analytic geometry and the theory of probability. He published The Doctrine of Chance: A method of calculating the probabilities of events in play. He showed that if the chance of throwing a six with one die is one in six, then the chance of throwing two sixes with two dice is one in 36. This calculation is often used by police and prosecutors to show, for example, that the chance of a man having two wives die by drowning in the bathtub is exceedingly small. We apply this method to the prosecution case with the following result. 

 

Note that the estimates of each occurrence listed below are my estimates, however I believe that they are very conservative indeed; and thus an analysis by a statistician is likely to result in much higher odds against Scott's involvement. Note also that Laci was identified only to one in 2 billion, and thus one must concede that it is many times more likely that her body was not the one found in the bay than it is that Scott Peterson was involved in any way.

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 That Scott could get the body over the side without sinking the boat.

The prosecution refused to test the boat themselves and violently opposed the introduction of a video made by the defence showing the boat tipping over. The video did make the point that as the size of the boat increases, the chance of tipping it over decreases. We have erred on the conservative side (i.e. in favor of the prosecution) – the chance of success is probably much less.

One in 10

 That both bodies would be found separated in space but within 24 hours of each other.

It is very unusual for flotsam or jetsam to arrive closely in time. Considering that these were the only two pieces which supposedly 'washed ashore' that is very unusual indeed. It is known for such items to surface 10 years or more later. A fairer estimate would be 1 in 112 * 2, i.e. 1 in 224 but once more we have favored the prosecution. If this was a coincidence, and there is some evidence it was, it should be the only one we should accept. (Laci's body wasn't found for 112 days and nothing was found in the next 112 days or ever - the searches were continued).

One in 10

 That Scott would ask Amy Rocha over for pizza.

About 16,000 homicides occur per annum in the USA. If as many as 160 of those responsible for these acts invite another person over on the night of their planned offense, the odds are 1 in 100. This seems to be a very unusual occurrence, but we have erred on the conservative (i.e. in favor of the prosecution) side.

One in 100

 That Scott would agree to pick up the gift basket. Once again we assume that no more than 160 of these persons would interfere with their own plan or alibi – a very conservative estimate. This, plus the estimate above, multiplied as they must be, give us 1 in 10,000 against Scott's guilt - just these two items!

One in 100

 That Scott would go on computer at home and not tell police - would 'stage' the curling iron and bench.

As an 'alibi', this is so weak and incomprehensible it seems extraordinarily unlikely.

One in 100

 That Scott would not use sane 'clue' to abduction - dry pot on stove, food melted on counter, wet clothes in washer.

Any of these or many other things would point to an abduction. Dumping her purse and other items in the bay or even around her car would work also.

One in 100

 That Scott would describe Laci wearing black pants (which match witnesses descriptions).

No one could explain why he would lie about this. It seems much more likely to be the truth, however we have set the odds as above.

One in 100

 That Scott would have mentioned the mop and buckets.

If he were guilty, why would he do this? What would be the purpose?

One in 100

 That Scott watched Martha Stewart.

Once again, to what purpose? How could it help him?

One in 100

 That Scott would tell the police that McKenzie is protective of Laci.

This negates his supposed 'abduction' alibi. What is the benefit to him?

One in 100

 That Scott would check his voice mail while driving to warehouse.

Why wouldn't he be much more concerned about the supposed body in the truck and the risk of any accident, no matter how slight?

One in 100

 That Scott would transfer the body to the truck, then from there to the boat and not tow the boat to house and load the body once only.

The prosecution made the point that he was well shielded from observation at home. Why then would he transfer the body once more in a busy place where anyone could come by at any time?

One in 100

 That Scott would drive with the body in the boat with a cover that cannot be secured to boat.

Once again a prosecution theory unsupported by facts also makes no sense.

One in 100

 That Scott would plan killing AND THEN start a relationship with Frey.

What adult with the slightest amount of common sense would combine these two? The jury claimed that this was what convinced them of his guilt, although it was not valid evidence of anything. How many killers would do this?

One in 1,000

 That Scott would plan to put the body in the bay and would not conceal the supposed plan (or boat purchase) carefully.

Despite all of the claims of the 'secret' boat, no proof of this was offered, and nothing indicated Scott proceeded with the purchase in any unusual way.

One in 1,000

 That Scott would not use $1 drop cloth on flat bed allegedly used to make the supposed weight(s) and dump it.

He could have used a drop cloth, he could have used plastic bags from his business or even newspaper. He made no attempt to disguise what he did.

One in 1,000

 Scott would make multiple weights and keep one that matches those used on body.

Making multiple weights seems extraordinarily peculiar. He could have poured water in the bag and made one large weight, bag and all.

One in 1,000

 That Scott would kill Laci the day before Christmas with dinner planned with family that evening.

Of all the times one would choose for such a crime this seems to be the very worst possible choice. What possible reason could Scott have had for this choice?

One in 1,000

 That Scott would put the leash on the dog - then take it off - then tell police.

Why take it off if it was an 'alibi'? Why put it on at all? What is it supposed to mean? It's too odd to find credible.

One in 1,000

 That Scott would use the computer at warehouse with the body in the boat or the truck.

How many killers would fool around for two hours with the body in the truck or the boat? It's the ultimate 'hot potato' – any actual killer would want to get rid of it as quickly as possible.

One in 1,000

 That Scott would stop at corner store on way to bay.

Once again it's the ultimate 'hot potato' – any actual killer would want to get rid of it as quickly as possible.

One in 1,000

 That Scott would leave boat and body tied up at dock while parking truck.

What an insane 'plan' – to walk away and leave the body in the boat unattended for several minutes while he parked where any passer by could see what was in the boat, even if covered.

One in 1,000

 That Scott would use the bay instead of a lake or burial.

The best place for a body is deep water. He could have dumped the body in a remote lake that night or buried it elsewhere and then used the bay trip as an alibi.

One in 1,000

 That Scott would use any boat on his first trip to bay.

What was his 'plan' if there was a problem at the bay and he couldn't use it? He was running out of time to do anything.

One in 1,000

 That Scott would use an area of the bay shallower than his swimming pool.

Why not rent a cabin cruiser, motor out to deep water, and dump the body there? Experience has shown it would never be found, and there would be no location to search.

One in 1,000

 That Scott would use an untested boat.

What was he to do if the motor wouldn't start (as the police found) or it died a few hundred yards from shore? It is doubtful that 15 or 20 people per year would make this choice - it is doubtful that one would.

One in 1,000

 That the baby would have no animal feeding.

How did the uterus 'tear' open? Over time? If so, why was there no animal feeding – or any sign the baby was ever in the bay?

One in 1,000

 That the baby would make it through the rocks and so far up on to shore.

The supposed track was a hazardous journey indeed, yet the only damage (a 'tear') was supposed to have been made by the police trying to pick it up. This seems to be a very remote possibility for a crime that was very unusual in and of itself.

One in 1,000

 That Laci's body would make a track that was not computable (according to Dr Cheng).

  1. Dr Cheng said there was no explanation for Laci's body being found where it was.
  2. When the tides and current are back tracked from where he body was found, they lead to the Albany Bulb.
  3. When buoys were dropped off the Albany Bulb they made a track to where Laci's body was found.

The time sequence for this would be 24 to 48 hours before the body was found. This eliminates Scott. We are once again using an extremely conservative value for this.

One in 1,000

 We find grass in the tote/purse. Servas reports grass on the leash,

Why would Scott do this? Why was there no grass on the leash when he came home?

One in 1,000

 Laci vanishes Dec 24th with Croton watch. A Croton watch was pawned days later.

A very remarkable coincidence indeed. What is the likelihood of this?

One in 1,000

 That Scott would make weights ahead of time.

No cases are known where a killer pre made weights. In all cases, they used something they had at hand or at most, purchased cement blocks for this.  Two would weigh 50% more than the four weights they assumed.

One in 10,000

 There was no evidence at house.

Policemen, doctors, scientists and other experts have all failed at this. When given up to a week to clean up, repaint, remove flooring and the like, evidence was still found. Scott had no time for this and yet not even the FBI could find the slightest trace of evidence, nor could dogs find anything evidentiary. How could Scott manage it first time out?

One in 10,000

 There was no evidence in the truck.

How could Scott manage it first time out?

One in 10,000

 There was no evidence in the boat.

How could Scott manage it first time out?

One in 10,000

 That cadaver dogs never found scent where Scott was - the only good scents led away from his locations. This is extraordinary.

One in 10,000

 That Scott could sink the body with only 32 lb and it would not be found during a very long search that cost $1 million.

This was one of the most extensive and expensive searches ever made. The weight used should have had the body return to the surface in a few days yet it was never spotted.

One in 10,000

 That the baby would 'separate' from the mother.

No mechanism is known to medicine or science in these circumstances. The cut or tear in the uterus makes 'coffin birth' impossible. The only ways in which a baby can be released from the mother is by birth or by C-section. Since testimony was offered that Laci didn't give birth to Conner then we must assume that someone cut him from her living body.

One in 10,000

 That Scott would want to kill Laci and would do it.

About 2.5 in 100,000 pregnant women are murdered, however the chances that Scott would kill Laci are much, much lower.

One in 100,000

 The twine would tie itself around body or slide over the head and then tighten around the neck.

Neither of these guesses is possible. No experiment can be constructed to replicate this. The only reasonable possibility is that someone tied this around Conner after he was removed from Laci's body.

One in 10,000,000

 The burglary would happen within 100 houses of Laci's abduction and on same day.

The homicide rate for pregnant women is about 2.5 per 100,000. The burglary rate is about 726 per 100,000. Multiply these two and the chance of them happening on the same day in the same house is about one in 2,000,000,000. Within one hundred houses of Laci's it is about one in 20,000,000 – we round it down to one in 10,000,000.

One in 10,000,000

 The uterus would be 2 - 3 weeks post partum within hours of baby's 'release'.

Again, simply impossible. The only conclusion is that she was alive when the baby was removed. One in 10,000,000

One in 10,000,000