Tenant stealing electricity

[Carol Frome]

Hello, Im trying to sort out how best to handle this. My former property manager was overbilling me like crazy and never gave me receipts for materials. He is retired now. 

Last spring I instructed him to rent a vacant one bedroom apartment, which he did almost immediately. Months later, I found out he had rented it to his neice. 

After she moved in, my quarterly water bill shot up from $300 to $900. He claimed he couldn't find the cause.

Now, in winter, my electric bill for the common area has also shot up. It was $45 a month. It went up to $200 and something, then to $300 something, and now $600+. We finally figured out after shutting the common area breakers off that "someone" moved the breakers for her apartment onto the common area. 

I still owe him money $2600. I already paid him $2000, even though I'm sure he was overbilling me.

I'm thinking of paying the electric bill and just not paying the former manager-uncle. The tenant is 19, pregnant, appears to party a lot, and she claims she has no lease (she does) and seems to be clueless about utility bills (her lease says she is responsible for heat and electricity). I suspect that uncle manager had been paying her bills other than the water, which I pay for everyone. But now he seems to have stopped. She got her first propane bill. Electric then skyrockets.

The former manger and I share the same lawyer. In fact, the lawyer recommended him.