Police identified the victim as Koji Suzuki, a man in his 60s hailing from Yokohama, and said he died from a single gunshot wound to the head.

They said investigation shows that a Filipino man who owed Suzuki money had hired the gunman who killed him.

Suzuki was attacked by two men on a motorcycle Tuesday afternoon as he was traveling by car with his Filipino common-law wife along on a highway in Tayug town in Pangasinan Province, north of Manila.

The gunman, riding pillion, shot Suzuki with 12-gauge shotgun, killing him. But the shotgun malfunctioned after the first shot, prompting the hitman to use a knife to attack Suzuki's wife.

She was stabbed seven times in the chest and abdomen but survived and identified the debtor, Eleorie Arzadon, as the one driving the motorcycle, police said.

Arzadon has been arrested and a manhunt has been launched to arrest the triggerman, they said.

Suzuki had been living in the province for three years.