RIO DE JANEIRO – Two brothers were charged with killing their father, a local Afro-Brazilian religious leader, by knocking him out with sleeping pills and then burying him alive, investigators told a Brazilian news website.

Antonio Valente Filho, chief of police of Timon, in Maranhao state, told Globo TV's G1 website that the brothers, ages 18 and 21, confessed this week to planning the murder. They told police their father was a violent man who drank too much and didn't accept their homosexuality, said Filho said.

A neighbor was also questioned about whether he helped the brothers dig the hole, Valente Filho told G1. Neither the suspects nor the victim were named.

The two men gave their father a stronger dose than usual of his sleeping pills and buried him while he was unconscious, G1 reported. An autopsy confirmed the victim died underground of asphyxiation.

"He really was buried alive," Valente Filho told G1. "We are investigating the real motive for the crime."

The chief said police are investigating whether the victim's role as head of a local Afro-Brazilian religious congregation may have been a motivation for the killing.

"We believe they might have been fighting for control of the ceremonial grounds," Valente Filho said. "We don't think this was just over their fights regarding the sons' sexual orientation."

He told G1 that after the neighbor told others about the grave they dug together, the brothers confessed to an uncle, who called police.

Calls to Timon police on Saturday were not immediately returned.