A Filipino man poisoned his four-year-old son before killing himself in a fit of jealousy on Monday after believing his migrant worker wife was having an affair with another man.

At 11:30 am on Monday, Rhandyl Cruz, 43, poisoned his son Zian Paolo in their house in Tondo, Manila. Police said a bottle of muriatic acid was found at the crime scene, the Philippine Daily Inquirer reported.

Police believe Cruz forced the boy to drink the acid after they found a half-full bottle beside the child’s bed. Cruz then stabbed himself several times in the stomach, causing his death. A suicide note and a kitchen knife were recovered from the scene. Cruz’s 17-year-old son and aunt discovered the bodies and called police.

Police Superintendent Carlo Manual, a spokesman for Manila Police District, said Cruz suspected his wife was having an affair while she was working in Qatar. Manuel said Cruz had threatened to kill their son because of her infidelity. Manual said the bodies will undergo an autopsy.