How do you solve this hypothetical situation about blood analysis and car accidents?

I’m no forensic analyst but I feel investigators could extrapolate that with a timeline.

The crime is the same, DWI, murder, etc. I think that would be the problem, not the BAC.

@jca2: What do you mean?

I mean if you kill someone, you’re looking at criminal charges for murder and you’re getting charged with DWI too. In your hypothetical situation, are you arrested?

If you kill someone, all they have to establish is that you were legally impaired at the time of the fatal accident. How drunk you were and when is irrelevant.

@cookieman: Yes, that was my first point which I don’t think was understood by the OP.

Sobriety tests only show how drunk you were at the time of the test.
If someone is dead, the driver is responsible whether they are drunk at the time or not.

If one has had any alcohol at all and drives soon after, if a fatal accident (or any accident occurs) you can be charged with driving while impaired. You don’t have to register a minimum blood alcohol content to be charged, because the accident is evidence that you were impaired.

And, if you left the scene to go have another drink, you’d be guilty of hit and run and also wanton disregard for leaving the scene of someone who was injured or dead.

I suppose you are trying to the discover if it is possible (but not necessary) to figure out the amounts of alcohol consumed before and after the accident.
Blood alcohol level alone won’t do it. But it is possible if that test is combined with liver enzyme test for ADH and ALDH, and a complete urinalysis

It takes the liver time to breakdown alcohol. If the alcohol was consumed hours before you could expect to see more of one enzyme than if the person was tested right after consuming. Since every person is different you would need to do follow up control work to determine that person’s specific metabolism and alcohol breakdown rate.
Also, if you know, or have a sample of, the alcohol consumed both times you might be able to get additional verification from the flavoing and coloring products added to the drinks.

Science was able to determine what Otzi the Iceman ate 5000 years ago. They can figure out how much alcohol was consumed and when, if they are willing to spend the time, money, and resources.