Buying a property with a terrible tenant....help!

[Patty Capson]

I am closing on a Triplex in Aurora, Co this week. One of the tenants has 6 months left on their lease, but needs to be removed. The other tenants have witnessed drug deals, her apartment is filthy/borderline hording. The other tenants have complained that they are having mouse and roach issues since she moved in a year ago.  Unfortunately the previous landlord kept no records, so I have no record of timely payments and the lease that is in place is super vague. How do I approach this?  

The other two tenants are awesome and I don't want to loose them.