Marcelo Costa de Andrade was born in 1967 in Rio de Janeiro into extreme poverty and an abusive household, and had worked as a rent boy from childhood.
Between April and December 1991 he killed fourteen boys aged between six and thirteen in the hill districts of Rio and Niteroi. He approached them in the favelas and on the street, offered them money or told them he would take them to see a religious statue, walked them into the scrub, and strangled them. He assaulted several of the bodies and, in one case, drank blood, which gave the Brazilian press the Vampire of Niteroi.
His explanation, given consistently and apparently sincerely, was religious: he had absorbed from a Pentecostal upbringing the idea that children who die go directly to heaven, and he said he was sending them there and envied them for it. He killed his own half-brother.
He was arrested in December 1991 and found incompetent to stand trial on April 26, 1993. He was committed to the Heitor Carrilho psychiatric hospital in Rio, escaped in 1997 and was recaptured, and has been detained since.
The case is periodically revisited in Brazil in arguments about the indefinite detention of the criminally insane, and about whether he could ever be released.