Contractor doing work in a property became a squatter

[Sharon Klein]

I had allowed a contractor/handyman doing work on various properties I manage and own to live on site while he was doing the work in one of the apartments.  He just finished his last job and he is refusing to leave the property and is squatting stating that I will have to evict him.  Somewhere along the way the relationship started to sour.  He knew he needed to absolutely be gone by the 15, but now he is refusing to.  He has been in this particular property working for about 5 weeks. Unbeknownst to me he started receiving mail there.  I think he had this planned. Any advice?  Is he considered a tenant under the law and must be evicted or is he a trespasser?