10 minutes before the murder: Expect to get an accusation of accessory to murder, conspiracy to murder and a few additional tomes of the penal code. We all know you are innocent, but you should better find a good lawyer just in case instead of wasting your last free minutes arguing on the internet.

But if you'd like to tell the fall, I'm sure some prosecutors wouldn't dig too hard to find the guilty party.

Edit: subpoena is not a criminal charge afaik is what I’m saying

While a bit more extreme than your example, there have been multiple cases where the parents of a school shooter have been held responsible because they provided access to a weapon when there were warning signs.

On the less extreme end of the spectrum, this is the same reason why you have to pretend that you are buying a "water pipe for tobacco" and not a bong if you don't want to get kicked out of the headshop (in places where that is still illegal).