San Francisco Airbnb hosts not playing by the rules now face a new challenge: private investigators out to catch them in the short-term rental act. However, as Bloomberg reports, the latest salvo in the ongoing battle between the San Francisco-based company and regulators wasn't fired by city officials, but rather by ousted tenants seeking revenge — and private dicks are reaping the benefits.

“Unfortunately, or fortunately, depending on how you want to look at it, it’s a decent living in San Francisco right now being an investigator doing these kind of jobs, because here are so many of them,” one such investigator, Michael Joffe, told the paper.

Here's how it works. Say a landlord no-fault evicts a tenant under the guise of an owner move-in, but then instead of actually living in the newly open unit decides to rent it out on Airbnb. What's a displaced resident to do? Well, if you're like Brian Grzybowski, you fight back.

Grzybowski says he and his wife were booted from their Potrero Hill apartment last year after his landlord said the space was needed for a relative. Grzybowski found other housing not too far away, although at $5,500 a month his new place cost $2,550 more per month than his old apartment. He then noticed his previous home for rent on Airbnb — which would be in violation of San Francisco law.

Grzybowski contacted a tenant lawyer and hired Joffe to determine if the place was being used for short-term rentals. Under the watchful eye of attorneys from both sides, Joffe looked over the unit and noted tiny hotel-like soaps and shampoos that suggested the place was indeed being rented out for short-term stays. The case was settled out of court.

Airbnb, for its part, says it opposes the alleged wrongdoing private eyes like Joffe are hired to uncover. “We strongly oppose illegal hotels and bad actors who remove housing from the market,” company spokesman Nick Papas told Bloomberg. “We’ve removed thousands of listings from our platform that aren’t right for our community. We are committed to working with cities to address their specific needs.”

It appears that Airbnb now has a little help in that department, courtesy of private investigators and frustrated San Francisco residents who don't back down easy after an eviction.

Related: SF Supes Approve 60-Day Cap On Rentals From Currently Unregistered Airbnb Hosts