SAO PAULO—Police say the vocalist of one of Brazil's most popular rock groups has been found dead in his Sao Paulo apartment.

Inspector Itagiba Vieira tells reporters that Alexandre Magno Abrao's driver found the singer's body sprawled on the apartment's kitchen floor Wednesday.

The 42-year-old Abrao was the lead singer and composer of the Charlie Brown Jr. band.

Vieira says the exact cause of Abrao's death is unknown but "apparently he was not murdered."

He said an "overdose of medicine or some other substance may have killed him."