Tenant got locked in bathroom

[John Smith]

My tenant allegedly got locked in the bathroom. He called locksmith which cost 350$.

Now, tenant wants me to deduct the amount from the monthly rent.

Generally speaking , whose responsibility is this?

[Malcomb Stapel]

Quote from @John Smith:

My tenant allegedly got locked in the bathroom. He called locksmith which cost 350$.

Now, tenant wants me to deduct the amount from the monthly rent.

Generally speaking , whose responsibility is this?

 Have them send you the invoice from the locksmith, then call the locksmith and see what the full story is. Decide on course of action from there. 

If there is not invoice, then that should be the end of it.