I am cheating on my wife’s cooking with the cute chef next door (not really, but who said an intro can’t have intrigue).
Twice a week, signalling her with a triple beep on my car horn she opens her door and I slip in to sit restfully on her sofa while she serves my plate after plate of delightful Dim Sum. Of which I partake with gusto. Each session lasts for around an hour. After each episiode she does the washing up in hot soapy water (horror of horrors, she doesn’t rinse but simply wipes dry) and puts away the plates.
So here’s the question -
After one session last tuesday, she was murdered, apparently by someone she knew as there were no signs of forced entry.
What as the chances that when the CSI team (the real one not Gil Grissom) goes through the house they find “proof” that I was there?
Here are the parametres of my hypothetical…
My hair is short (I had it cut last week in a number three)
I am not suffering from any ailments or allergies, and do not have a cold (so I don’t sneeze)
All the plates and utensils I used have been washed in hot water as she’s a “clean as you go sorta girl”
There was no bathroom useage, and I did not open any doors, or ring the bell.
So am I safe, or do I have to go to the police before they ask my wife what I was doing there?
Ok…just to clarify a little, what I am trying to ask (with a slight sense of humour) is:
If I spend an hour inside a random room, what are the chances I have left behind DNA that would be / is likely to be detected in the instance that a murder is perpetrated in said room within 4 hours of my leaving.
Probably pretty good. The problem is whether they find it or not. If you have a buzz cut or something, it might be hard to find the hairs. Same goes with skin cells. All the stuff is going to be there, but whether it’s found is something else.
Fingerprints, on the other hand, are almost guaranteed unless you were consciously thinking about not touching anything/wearing gloves.
Or let’s put it another way…she also liked to throw 10 person dinner parties 3 x a week.
I am a male with kinda brownish hair…how many other males with similiar coloured hair are going to have left a hair in these premises? How many “samples” are going to have to be tested before mine is found?
Any act of a man, and especially violent acts as in a crime, cannot happen without leaving a trace.
Every time you exited the house you left something behind and you took something away. The question is, do they have a way to connect you with the evidence? They may have skin cells, but without you to compare them to they don’t do much good.
The thing is, if they find a skin sample, or a fingerprint, or a hair, or a blood sample, or a semen sample, they can try to match it in their databases.
But you probably aren’t in the databases. If you’re a suspect, they can demand a DNA sample, and use that to match to the forensic evidence left behind. But they take a skin cell and figure out from that which of the 6 billion people on earth it came from, because only have DNA samples from a minuscule fraction of those 6 billion people.
Same with fingerprints. If they have a suspect, and they have a fingerprint, they can see if the fingerprint matches the suspect. But they can’t look at a fingerprint and say, “Aha! This fingerprint belongs to John Smith of 1313 West Main Street!”.
Of course, if you’re the next door neighbor, you’re going to be a person of interest, because you might have witnessed something or you might be the perp. But they probably won’t nab you by finding a DNA sample at the crime scene and then subpoenaing DNA from everyone in the neighborhood. Rather, they’ll talk to the neighbors, and one neighbor will mention noticing that you seemed to be spending a lot of time over there lately. And then the cops start to build a case against you, and pretty soon you’re in handcuffs while a lab tech is swabbing your cheek.
Unless, of course, you once were a suspect in a serious criminal offence in the past (and they took your fingerprint). If they do find you and take you in for questioning, the chances of getting away with it are very slim - they’ll hook you up to one of those advanced polygraph that can detect the slightest muscle twitch.
Or were a Federal Employee, or visited the police station as part of a class field trip. When I started the paper work to get my NIH badge, I saw my hopes for a glamorous life of crime go up in smoke.
I imagine you meant this facetiously, but some folks might be misled by it. The only lie a polygraph can detect is whether you’re lying about having an orgasm. The only investigative value they ever have is in scaring a suspect into telling all.
