You need to tell us more details of this to determine if they were in fact trespassers. But going just by what you put in the subject line you indicate that they were permitted on the property as your tenants and that your problem with them is that they had not paid to you the agreed upon rent. In that case, they are NOT trespassers. They are tenants and the police cannot remove them from the property without a court order. So, like it or not, you have to go through the eviction process to get them out.