what if say the cash came with a note telling you to put it toward something specific like keeping your house?

At least then I'd have a narrower field of people to suspect, since I know who I've spoken to about that and who I haven't. I'd still set it aside until I knew more about the situation, the reasons and motives, all of that. I couldn't in good conscience take it if it would put the person it came from in a worse situation than I'm in already, if that makes any sense. It'd just keep chewing on me.

Have at it.