(NewsNation) — Squatters taking over people’s homes can be a nightmare that’s hard to wake up from because the laws can be murky. Now, some homeowners are taking matters into their own hands to get their homes back.

Squatting is when someone starts living in an often vacant property when they may not have the legal right to. Squatters can leave a mess and scare those living nearby.

But according to one lawyer, squatting itself is not a crime — trespassing is. Authorities get to decide where the line is drawn.

In one St. Louis neighborhood, trash is piling up at a home in foreclosure. Last month, the FBI raided an abandoned home in New Orleans, Louisiana, where neighbors say alleged drug users were living.

Last year, in Las Vegas, a man who was away for months came home to find a stranger in his apartment and shot her. Police determined it was self-defense.

“I was scared to death when I heard the noise, nobody comes to my place without an invite,” Jermaine Pritchett said.

In a video shared with NewsNation, Pritchett shows the mess left in his home by a squatter while asking, “Do you just go into people’s places? So what if it’s open, is it yours? Do you pay rent here?”

There is an important legal difference between squatting and trespassing, a law professor explains.

“Trespassers are criminals. They have no right to be on your property. But squatters, they do have rights. Often they have paid a utility bill and oftentimes they are former renters,” said law professor Danny Karon.

Karon advises homeowners dealing with squatters to call the police rather than take matters into their own hands.

“They need to fast-track these housing cases to give rights and better rights to these property owners,” Karon said.

Some cities have also set up rapid response teams to deal with squatters, with prosecutors who make immediate judgments on who lawfully owns the property. They can also fast-track lawsuits to get you into court quickly.