The Anglican bishop for Brazil's northeastern state of Pernambuco was killed along with his wife, law enforcement officials in the state capital of Recife said Tuesday, and their son is the chief suspect.

Edward Robinson Cavalcanti, 68, and his 64-year-old wife Miriam were stabbed to death on Sunday in their home in the city of Olinda, a spokeswoman for the state's public safety department said. She spoke on condition of anonymity, citing internal regulations.

She said the couple's adopted son Eduardo is suspected of killing them "for reasons that remain unclear."

She said the son stabbed his father during a heated argument and when his mother tried to stop him he plunged the knife into her.

The son was hospitalized after he tried to commit suicide by drinking poison, she added.

Police inspector Joao Brito Alves told the Globo television network that he had learned that the son had a "violent temper and was frequently under the influence of drugs."

Cavalcanti headed the Philosophy and Human Sciences Department of the Federal University of Pernambuco.

The Roman Catholic archbishop of Olinda and Recife, Rev. Fernando Saburido, said Cavalcanti's death was a "loss for Christianity."

"He was sensitive to social issues and concerned with problems that affected the poor," Saburido told G1, Globo TV's Internet portal. "He will be sorely missed."

Anglican pastor Miguel Uchoa told G1 that Cavalcanti "had a brilliant mind" and said, "He taught me everything I know about the church. He always defended the creation of a more just society."

The killing shocked Cavalcanti's neighbors.