Help me settle a disagreement, please. Is it a crime to spend money that you stole, or was the crime committed during the thievery?

I think spending money that you stole could become a money laundering crime depending on what you spend it on. Buying something with significant resale value using stolen funds does sound like laundering. Likewise gambling some of it and pretending you "just got lucky."

Also, you have to pay taxes on your income, even if it's stolen. If you've been tracked spending thousands you didn't earn, like Al Capone, you'll be charged with tax fraud and/or evasion.