# Serial Killer DNA



## wainscottbl (Oct 5, 2015)

So the killer rapes the women, then leaves them on a beach. 

How possible is it that he would leave no DNA at all? Because there is a cop that suspects him, and it is easy enough to get the DNA without a warrant for the cop. All he needs is the glass he was drinking out of, which is easy enough in this case. No hair, no semen, no fingerprints. The latter is easy enough. Is there any way that this killer could repeatedly leave no DNA?


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## TipGrundlefunk (Oct 5, 2015)

For there to be no DNA the killer either has to leave none or destroy it in some way, there's a third way I'll mention later.

Forensic teams dress to prevent contaminating crime scenes, so your killer could be familiar with these precautions (a bit Dexter though), or your killer could know how to destroy DNA such as strong oxidizing agent like bleach or hydrogen peroxide. He could of course be using bleach not knowing that it is destroying his DNA, a fortunate (for him) accident.

Also it is impossible to distinguish the DNA of twins (triplets, etc.), so if one commits a crime and there is no way to tell who committed it from circumstantial evidence then the enforcing agencies cannot do anything - you cannot imprison an innocent person and there is more than a reasonable doubt one of the twins is innocent, it's a certainty. This was used to excellent effect in a well known French thriller.

There's all kinds of angles you can find.

Tip


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## J Anfinson (Oct 5, 2015)

A single hair can be incriminating so he would need to shave his whole body to be safe. Wear a condom and use spermicide. Wear gloves. Probably burn the body. 

Put yourself in his place. How paranoid do you think you should be?


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## Plasticweld (Oct 5, 2015)

You guys must not live on the ocean.  I spent a few years as a commercial fisherman, so have some idea of what the ocean and sea life do to dead meat. 


A body left in the ocean, say the guy dumps them at low tide and they are washed out to sea and then return with the tide to be washed up the following morning any traces would be gone alone with a fair percentage of flesh.  After 3 days next to nothing would be left.  


The only place better to dispose of a body than the ocean is a hog pen....did I ever tell ya about the time I.....


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## J Anfinson (Oct 5, 2015)

Not being paranoid enough is what gets people caught.


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## wainscottbl (Oct 5, 2015)

I will have to consider that. Yeah, on TV version of "Hannibal", which was alas cancelled, Lecter wears a plastic body suit. Of course he ate his victims, not raped them. I guess you'd have to make a little zipper if you were a rapist. But the beach factor makes it easier. The water washing it away was not even my intent. And I can use the bleach perhaps. It is an Oregon beach, and those tend to be rocky and have clashes with the rocks. A lot of splashing. And the tide helps. I'll work with it.


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## ppsage (Oct 5, 2015)

What I don't get is why more of these crooks don't plant dna. Hang around a bar and tweezer up some dude's butts or search a lover's lane for full prophylactics.


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## wainscottbl (Oct 5, 2015)

ppsage said:


> What I don't get is why more of these crooks don't plant dna. Hang around a bar and tweezer up some dude's butts or search a lover's lane for full prophylactics.



The guy would have to at least be a person of interest I think. Johnny the Mail Man has to fit the facts--times, etc. It's hard to frame someone unless they are associated with the case. Even a serial killer. Once the timing and other evidence did not match up with the framed guy at the bar, it'd be over. But frame your husband for killing his mistress when you killed her. yeah, that can work.  Two birds with one stone. Kill the harlot, punish the cheater.


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## ppsage (Oct 6, 2015)

The cops won't know whose dna it is, they'll just know it ain't yours.


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## wainscottbl (Oct 6, 2015)

ppsage said:


> The cops won't know whose dna it is, they'll just know it ain't yours.



Oh....yeah!


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## LeeC (Oct 6, 2015)

Can't recall exactly, but wasn't planted biological evidence the idea in Scott Turow's Presumed Innocent?


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## TipGrundlefunk (Oct 6, 2015)

Plasticweld said:


> You guys must not live on the ocean.  I spent a few years as a commercial fisherman, so have some idea of what the ocean and sea life do to dead meat.
> 
> 
> A body left in the ocean, say the guy dumps them at low tide and they are washed out to sea and then return with the tide to be washed up the following morning any traces would be gone alone with a fair percentage of flesh.  After 3 days next to nothing would be left.
> ...



I am no expert on this but from what I know salt water preserves DNA. Also they have been able to extract victims DNA from organisms that feed on the dead body, again I don't know to what extent this is possible but I do know salt water is not going to destroy DNA.

Tip


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## walker (Oct 6, 2015)

I don't think it is likely that the killer would leave no DNA, especially repeatedly.

However, it might not be found. 

I remember listening to the lab tech's testimony in the Trayvon Martin case. At the time it seemed to me that much potential DNA evidence was not gathered. The scenario was a lab tech, on an average day, not knowing that the body or the case was particularly important, going through the motions, short-cutting procedures, and so on.


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## wainscottbl (Oct 6, 2015)

walker said:


> I don't think it is likely that the killer would leave no DNA, especially repeatedly.
> 
> However, it might not be found.
> 
> I remember listening to the lab tech's testimony in the Trayvon Martin case. At the time it seemed to me that much potential DNA evidence was not gathered. The scenario was a lab tech, on an average day, not knowing that the body or the case was particularly important, going through the motions, short-cutting procedures, and so on.



Yes, and a serial killer case is not like Treyvon Martin's caase. The search for DNA would be intense. But the water could wash it away. And bleach could be used. It's a difficult aspect. It's more of a side plot though, though it does cause a very major plot turn. We'll see how I can manage it.


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## Doc Martin (Oct 7, 2015)

I have an idea. Your rapist could be a non-secretor who had a vasectomy. That would make IDing him via semen very difficult. He would have rare detectable sperm and no ABO antigens in the body fluids. This would not be too far fetched as 25 percent of the population are non-secretors. As far as no other DNA on the victim; I have no idea how to explain that.


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## PaperbackWriter (Oct 17, 2015)

You might want to look into the effects a night of rain has on the body.


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