(Sao Paulo, Brazil) Brazilian police are investigating whether a possible serial killer is behind the murders of more than a dozen gay men in a park in suburban Sao Paulo.

He says police are not sure whether a single person is responsible. Undercover police are now patrolling the park at night.

Fortunato says he went public with the investigation to help warn people of the danger.

His comments were published Monday. Requests for police comment were not immediately answered.