BOSTON (WHDH) -- State and federal authorities say they have arrested the co-owners of two Boston-area massage parlors as part of an investigation into human trafficking and prostitution. A third suspect was arrested Thursday night.

Police collected evidence and towed a car from a Wellesley massage parlor Thursday. The parlor was shut down and the operators were arrested, accused of prostitution and human trafficking.

“Actually, I’m shocked. We’ve had excellent tenants for years,” said Ann Miller, building owner.

The building owners say the three suspects had only been renting the space from their son’s studio for less than six months.

“Good, clean operation. I don’t mind helping the guy out. And I don’t know how they can have what they claim going on because there’s not that much operation there and I feel sorry for the guy. I hope it proves his innocence,” a building owner said.

The three suspects ran massage parlors called Sun Spa, also known as the Spa Studio, in Wellesley, and Bodywork in Revere.

The attorney general and Homeland Security say the parlors were offering sexual activity between the masseuses and their clients in exchange for cash.

The owners of the Wellesley building say they never saw or suspected anything illegal.

“I don’t understand. I’m around here most of the time and I don’t see that activity,” a building owner said.

The three suspects will be arraigned Friday in separate courtrooms.