They move into homes without permission, never paying rent, the mortgage or any utility bills.
Squatting has become a major problem across the Valley - with dozens of unscrupulous people setting up camp in vacant houses.
CBS 5 News was there when Maricopa County Constable Doug Clark showed up at a Phoenix home near McDowell and 16th streets to tell a squatter that his free ride was over.
The squatter, Vincent Plato, said he'd been living there for the past month.
The real tenant, who was on the lease, went to jail, so Plato decided to move in.
"They just move in and make themselves at home in somebody else's house," Clark said.
The landlord said he had no idea that strangers were living in his rental house until he stopped by a few weeks ago.
But the landlord couldn't kick them out right away.
Real Estate Attorney Mark Zinman said that Arizona laws are pretty clear when it comes to squatters, which means that landlords often have to wait a month and complete the eviction process before they can legally get rid of their uninvited guests.
"They may break in through a window, but they will change the locks so they have the keys to property," said Zinman. "When police go there, they are not schooled to make that decision. They'll look (like) tenants because they have keys. A lot of them will set up electricity in their name and actually have an account that looks like they are valid tenants."
But what if the squatters do more than just set up house?
When Clark arrived at the Phoenix house, the kitchen stove and air conditioner unit were both missing.
Plato said that someone must have stolen the items in the middle of the night.
"I just woke up," said Plato. "I can't answer no more."
The landlord filed a police report, but chances are he won't see a dime and Plato won't do any time.
"You know, if they didn't pay any rent in the first place, he's certainly not going to be able to go after them in small claims court and recoup anything," Clark said.
Clark said that these squatters are well aware of Arizona law, so when they're kicked out of one house, it won't be long before they make themselves at home someplace else.
"I would say they are professional squatters," said Clark. "They know how the system works."
"I'm not no bum," said Plato.
Copyright 2013 CBS 5 (KPHO Broadcasting Corporation). All rights reserved.
A house known to be used by squatters in Phoenix went up in flames Wednesday night, according to the Phoenix fire department.The Phoenix fire department was called out to the 16400 block of 21st StreetMore >>
A house known to be used by squatters in Phoenix went up in flames Wednesday night, according to the Phoenix Fire Department.More >>