Most Helpful Guy
You're talking about pets and about drugs.
On the one hand, I think the pets is a thing, but drugs is another, completely different one.
Lousy at it might appear, buy a drugs test without telling him, and wait a bit longer, and have him pass it.
Only if he passes the test, give him the benefit of the doubt, but he fails, he will have lied, and you'll be better alone.