Tenant interfering w/ pest control

[Deb Smith]

My tenant informs me of rats in unit. I hire pest control.  Tenant interferes with process from day one, but I'm not told about that for about 2 months. ( they remove traps, add more traps, don't let pest control in the unit, etc. )  3 weeks ago is when I'm informed that tenants are interfering...I have a meeting with them, pest control technician and his supervisor explaining NOT to Move, add or do anything. Let them do their job. I put it in writing if they interfered one more time they would responsible for the pest control bill and any future company I would have to hire because this company is going to stop coming out.  The very next week they do it again!!! I go in and the trap is gone. She put it outside in the utility shed. The rats are INSIDE!  They keep blaming me for the problem.  I'm at a loss at this point.  The last thing I want to do is evict, but how do I get them to stop interfering ? Make them pay that bill? I don't usually give empty threats.....if I say im going to don something, I do it.