Sailson Jose das Gracas, a man living in Rio de Janeiro, Brazil recently confessed to the murder of 39 women.

“[I started] robbing purses and small things like that. As I got older, I started having different thoughts. My thoughts started changing. From stealing, I started thinking about killing,” Gracas said during his interview with Globo TV.

Instead of killing impulsively, Gracas took a different approach. He preferred to stalk his victims before murdering them.

He was arrested on Wednesday, when cops became suspicious of his possible involvement in the murder of a woman named Nova Iguacu. Upon being detained, Gracas confessed to the murder, as well as a handful of others.

Gracas describes his murders as a pathological need that he cannot control.

“When I did not kill, I would get nervous, I would pace around the house, and then when I killed, it calmed me,” Gracas said to Globo TV.

Gracas is not only suspected to have killed 39 women, but also a 2 year old boy, who was the son of one of his victims. The process of examining each body has proved to be tedious, but police are determined to take every precaution in order to obtain justice for these brutal murders.

“What is done is done. If I leave here in 10, 15, 20 years, I’ll go back to doing the same thing,” Gracas said.