Need to evict tenant with no rental agreement

I'm in escrow on a 4 unit building and the occupied units have no rental agreements. 1 of the tenants is delinquent 5 months and the seller clearly has not made attempts to evict. I'm in New Mexico. I've got experience managing rentals, but I've never encountered no RA's because we've always had tenants sign. Can anyone give me insight as to what the process looks like getting this guy out and any pitfalls to avoid (other than trying to prevent him from dumping concrete down the drain on his way out lol)?