A hospital worker killed 39 people in 10 months out of "anger at everything and everyone", police in Brazil have said.
Thiago Rocha, 26, is accused of embarking on a killing spree in the central state of Goias, where he worked as a guard at a maternity and infant hospital.
Following his arrest, Chief of Police Deusny Aparecido told a news conference Rocha was a "cold person" and "killed out of anger".
"He had no link to any of his victims and chose them at random. It could have been me, you or your children," said Chief Aparecido.
"He felt anger at everything and everyone."
Rocha, who is said to have confessed to the murders, was detained on Tuesday and is awaiting a court hearing.
He reportedly tried to cut his wrists in his cell using a broken light bulb.