Marcelo Costa de Andrade was born on January 2, 1967, in Rio de Janeiro, Brazil. He grew up in a difficult environment. For part of his childhood, he lived in Rocinha, a favela in Rio de Janeiro. His mother worked as a maid and faced abuse from her husband. Due to these troubles, Marcelo was sent to live with his grandparents in Ceará for a while. He claimed that he earned a lot of money during this time. However, he returned to Rio de Janeiro after some time and was mistreated by the new partners of his separated parents. During this period, he was sexually abused by an older man.

As he grew older, Marcelo faced many challenges. He was admitted to a boys' school but had a hard time in his studies. He was bullied by his classmates, who called him names like "retarded." When he turned 14, he got kicked out since the school only accepted boys between the ages of 6 and 14. After leaving the boarding school, he began to prostitute himself. He later said that while he usually took an active role, he was once forced to be passive, which deeply troubled him. This experience led him to attempt suicide. Eventually, he was sent to a juvenile facility known as FEBEM, but he escaped after a few months and returned to prostitution.

At 16, Andrade moved in with a man named Antônio Batista Freire. Antônio supported him and introduced him to the Universal Church of the Kingdom of God. Despite this support, Andrade continued to engage in prostitution until he separated from Antônio and went back to his family. After returning home, he stopped prostituting and began working formal jobs to help with family bills and chores.

Throughout this period, Andrade regularly attended services at the Universal Church for about ten years. He also watched daily religious broadcasts. He believed that when children die, they go to heaven, which influenced his later thoughts. Andrade spent his time reading the teachings of Bishop Edir Macedo and even enjoyed looking at pornographic magazines. He listened to children's music, including songs by Xuxa, and had a peculiar habit of replaying a tape of his brother crying.

Marcelo Costa de Andrade was a Brazilian serial killer who murdered 14 boys in 1991. His crimes took place around Niterói, Brazil. The first known murder occurred in April 1991 when Andrade approached a boy selling sweets. He lured the boy away with false promises and attacked him. Andrade used stones to kill the boy before committing sexual assault.

Over the following months, Andrade would continue to target young boys. In June 1991, he encountered 11-year-old Odair Jose Muniz dos Santos begging for money. He convinced Odair to go with him under the pretense of visiting an aunt. Instead, he took Odair to a soccer field, where he attempted sexual abuse. After failing, Andrade strangled him. He later returned to decapitate the boy's body.

On December 16, 1991, Andrade approached two brothers, 10-year-old Altair and Ivan Medeiros de Abreu, in Niterói. He offered them money to help with a supposed religious ritual. They accompanied him to a deserted area, where Andrade attacked them. He sexually abused Ivan before killing him. Altair managed to escape after Andrade fell asleep.

Following the escape, Altair informed his family, leading to the discovery of Ivan's body by the police. When questioned, Andrade confessed to killing Ivan and admitted to a total of 13 other murders. He described each of his crimes in detail, showing a complete lack of remorse. Andrade claimed that he believed his victims went to heaven due to their young age.

Andrade's gruesome actions led to his arrest on December 18, 1991. After his capture, he was declared insane and was sent to a psychiatric hospital for treatment.