Sometimes signs aren't enough to keep trespassers away. For Julie and Del Spronk, it took dozens of calls to police and then the court system to get involved.

"What an eye opener," Julie Spronk lamented to WCCO. "Tenants' rights are not the same as squatters' rights."

The Spronks bought a property in Faribault, Minnesota for their adult son earlier this year. A few months after he moved in, the Spronks said the son left for an extended leave and locked the door behind him.

One night this summer, the Spronks drove by and found something they didn't expect.

"It was shadows and images really looming around in the darkness of the night," Julie Spronk recalled. "There were a handful of men walking around. A lot of them didn't have shirts, a couple of them had bicycles. The rest were on foot. I think every one of them had a book bag."

The Spronks called police, but one man, whom the family said was a friend of their son, then asserted his right to the property, which the Spronks refuted.

The back and forth went on for nearly two months.

"It's our lights, our electricity, everything we're paying for," Julie Spronk said. "It's our property and we're feeling very violated."

"If you have a squatter there you should be able to turn off the electricity," Del Spronk insisted. "I don't care if it's 20 below. If he doesn't belong there, they don't belong there."

Eventually the Spronks took the man to court — and he agreed to leave — but the time, money and stress they spent on the monthslong ordeal reveals some of the ambiguities and challenges with real estate laws in Minnesota. 

"Our policy makers and our courts have decided that on balance we want to tip the law in favor of the tenant rather than the landlord," Jon Morphew, a veteran real estate attorney in the Twin Cities, explained to WCCO. "So we've established this formal legal process a property owner has to go through to have someone removed from their property."

That process could take up to 45 days - and that's in addition to a 30 day notice required for evictions, Morphew added. Police, meanwhile, are also either enable or unwilling to wade too deep into the issue when property owners call about squatters.

"It's that delineation between it being a civil matter and a criminal matter," Morphew said. "If these people assert they have some claim of right to be there, those are the magic words in the trespassing statute."

In the Spronks' case, Morphew said there's not much to have done differently; the best advice he offers for property owners is to get ahead of the legal process by having an attorney and legal resources at the ready so they don't have to spend time looking for them after they need one.

He also advises all tenants to put everything in writing, even if it's for family.

For the Spronks, they also offered their own tips ahead of the winter: avoid having any vacant property.

"It's just a dangerous game to have your property be vacant because that's an opportunistic time for someone to move in and have all the rights that they need to become a tenant," said Julie Spronk.