This is attorney Bill here offering advice and help with this difficult situation for all.
My answer is confined to the law and legal information.
In relation to stolen equipment or equipment/ cymbals borrowed and not returned, you are right, that this is a crime.
The crime is theft larceny and conversion. Depending on their value, it would either be a misdemeanor or perhaps even a felony. But I'm sure if they are friends they would like to solve this amicably.
If you feel this is not possible, you would need to contact the police and file a complaint with them so they could investigate.
As far as money debts are concerned, that would be also a civil offense and dealt with through the civil courts.
If the amount is not great, under the $5000 mark it would be very straightforward to file a small claims court claim for the monies owed. The clerk of the small claims court gives the plaintiff a form to fill out with a nominal filing fee.
This is the legal way to go about things if things cannot be resolved in the near future.
For larger sums of money, you would be better to employ an attorney and sue through the civil court.
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