A rash of mansion robberies in southwest Florida is being blamed on a mysterious ring of ninjas, one of whom wears a fedora.

There have been at least six robberies in Collier County in the last three months that police say follow a similar M.O., the last one taking place April 30 at the home of Bill Kitchen.

Kitchen and his partner, Camilo Espinol, had just pulled into their driveway when they were greeted by three armed robbers in ninja outfits, one wearing a fedora.

"They confronted us in the garage as we got out of the car," Kitchen told WZVN-TV.

The two were brought inside the mansion and tied up while the robbers ransacked the home, he said.

"I have insurance, so they demanded everything in site, so I gave them everything. I gave them my watch, my wallet -- everything they asked for," Kitchen said.

The ninja robbers also stole Kitchen's car, which was later recovered a short distance away, ClickOrlando.com reports.

The FBI is taking the the ninja robbers seriously, and working with police in Windermere, WESH-TV reports.

Not all of the robberies involve ninja outfits, but in all cases, the suspects held their victims -- some of them elderly or children -- at gunpoint. The victims were also bound, either with zip ties or duct tape.

Trish Routte, program coordinator for Southwest Florida Crime Stoppers, admits investigators have their work cut out for them.