How to get illegal tenants out

[Mick Saavedra]

Hi all, just had a general question about the eviction process. 
We decided to terminate the lease of one of our tenants only a month into their lease due to various breaches of contract- including renting out the basement of the property to people not on the lease. Now, 30 days later, the tenants who were on the lease are gone, but the people living in the basement (who are not on the lease) are still there. Could I call the police and report them for trespassing or what would be the correct protocol to get them out? 

Thank you.