Legal Question in Criminal Law in California

If law enforcement wants to do a forfeiture or money, you need to show a legal paper trail for any money seized.

Is this some sort of a "I wasn't committing that crime, I was committing some other crime (gambling)" defense that drug people come up with?

If there's a final judgment in your criminal case that says the money came from selling drugs, then no other court will even consider -- let alone accept -- an argument that it came from some other source. But maybe the judgment didn't say that, or maybe it will be reversed on appeal. Then you could try to claim the money.

How to do that will depend upon why the government is holding it. Was it evidence in your criminal case? If it was, and if it hasn't been deemed the proceeds of a drug sale, then you may be able to get it back once the judgment is final. Offhand I don't know the process for recovering property that is being held as evidence, but the same procedure should apply to cash as to other types of evidence.

If the government instead obtained a court order that the money was forfeited, then that is a separate judgment that you will have to overcome. It may already be too late to do that. Or maybe the forfeiture case is still in progress; if so, you will have to win it. Proving that you got the money from a card game might defeat the government's argument, or it might not. I would need to know more about the facts and about what the government has alleged and/or proved.