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Sep-5-2008 13:57

Suddenly a thought dawned to me....
I want you to check if I might be correct.

If I happen to work on a case with 4 evidences, and I of some strange reason know or expect the case to have 3 suspects with real alibies.... - and I have another two suspects that don't match any of the alibies....

Then I don't have to check the alibi on those who don't match any evidence, because I know they will be fake? Those 3 real alibies must be among the other suspects that might match an evidence?

Are anyone able to help me confirm or tell this is a wrong conclusion? Don't ask me how I get that strange idea that the case might have 3 suspects with real alibi though, because that's a secret I would like to hide, it's some kind of magic I do to the case ;-)

Sep-5-2008 19:16

There is a way that you can work out how many suspects you have with real alibis. Some cases you may get a case with one more PE than there are real alibis - then 1 PE must match the killer and the others must match the real alibis. So yes you are correct Huglover.

Sep-5-2008 22:30

Each piece of PE matches one, and only one, suspect. That said, I would believe it is safe to say that if you have 4 PE, you'll have at least 3 real alibis. Not necessarily only 3, but at least three. Not sure if that answers anything, but I hope it helps.

Sep-6-2008 02:20

Yes Huglover you are right. Your hypothesis is correct

Sep-7-2008 09:09

I hate to differ, but it's not entirely correct. The only time it would be depends on the total number of suspects in that specific case. Jojo and Missy have it about right.

In theory, one would have to assume in Huglover's case that she's referring to would have the lesser number of suspects. However, it's never safe to assume, so I'd say that it's not entirely correct. I wouldn't go by what's said since it doesn't give specifically the total number of suspects. In each almost impossible case, you would have 7 fakes, thus 3 or 4 real alibis. Of course, I pointed out the obvious for a reason.

So, the entire conclusion (including the obvious), it just depends on the case. That theory is correct in only certain cases, and incorrect in others.

Sep-7-2008 09:15

Well since there is a way to check how many suspects you should have in total, then you can work out how many suspects there are with fake and real alibis. So if you can work out that there's only 3 real alibis and you have 4 pieces of evidence, then Huglover's got it right.

Sep-8-2008 10:28

I think this has been expressed somewhere else on these boards as the rule you can apply when you know you have four pieces of evidence and the minimum number of suspects, though I think it may only apply to IH cases and above. In these cases, you know that every person with a real alibi will have a piece of PE, so yes, if a suspect cannot be linked with any of the PE then you know they have a fake alibi.

It's got me out of a tight corner in AI cases a few times.