The owner of a New Zealand hostel is accused of drugging at least 16 male backpackers, then making videos while he sexually assaulted them.

Authorities say Michael Harris, 56, allegedly carried out the disturbing acts over a period of 30 months at the Mainstreet Lodge in Kaitaia. The victims are reportedly mostly 18 to 25-year-old overseas travelers.

Cops said images they have recovered depict Harris sexually abusing the young men, according to Sky News. Police want to talk to anyone who has stayed at the hostel over the past few years.

TVNZ reports that police have already received calls and emails from around the world in connection with the case.

"These victims are unlikely to know that something has happened to them, although they may have suspicions,” Detective Senior Sergeant Rhys Johnson said in a statement Wednesday. “We will deal sensitively with them and offer all appropriate support required.”