A Filipino man was shot dead by a police officer on Tuesday after he stabbed a man he was sitting next to on a bus in Davao City in the Philippines.

On Tuesday morning, Junie Luceño, 41, and his sister Winnie were riding a bus to Davao City Overland Terminal when Luceño suddenly stabbed the man sitting next to him in the head, ABS-CBN News reported.

Luceño then got off the bus and his sister followed him. Police officer Reynald Valdez, a member of the Traffic Group in the Davao City Police, was regulating traffic in the area when Winnie asked him to arrest her brother.

Valdez said Luceño tried to stab him and he shot him in self-defense. Luceño was killed after sustaining two bullet wounds to his body.  “I made him get down on the floor, but he suddenly stood up and attacked me. He almost stabbed me, that’s why I shot him,” Valdez said.

Luceño’s sister said her brother was not mentally ill but his motive for stabbing the man was still unknown. The man he stabbed on the bus was identified as 33-year-old Joel Salazar. He was rushed to hospital, but his condition was not known.