Police from Auckland and Waikato are now helping Northland staff investigate a man accused of drugging and sexually assaulting at least 16 young men who stayed at his Kaitaia backpackers accommodation.
Michael Harris, 56, was arrested last Monday after police raided his Main Street Lodge in Kaitaia.
Police executed a warrant under the Search and Surveillance Act after a complaint by a male tourist who told police he suspected something had happened to him while staying at the lodge.
More than 30 people have made contact with police following his arrest, and sixteen police staff, including four from Auckland and Waikato, are now contacting and interviewing those who have come forward, Detective Senior Sergeant Rhys Johnston said.
Alleged victims from around the world have come forward, including from Germany, Scotland, the UK and the US.