Manila - Four suspected kidnappers, including a former vice mayor and a policeman, have been arrested in the Philippines after they collected ransom for hostages they already killed, police officials said Friday.

The hostages, retired pilot Demosthenes Canete and his driver Allan Garay, were killed on the night they were abducted on June 27 in Cavite province, just south of Manila.

But the kidnappers still demanded ransom from the victims' family, according to Senior Superintendent Leonardo Espina, chief of the police anti-crime and emergency response.

Espina said two of the suspects were arrested during a ransom pay-off arranged by Canete's family with the assistance of the police on July 4 in Manila.

"Operatives monitoring the pay-off promptly arrested (the two suspects) as they picked up the ransom," he said. "The ransom takers admitted during investigation that they were acting on orders (of a police officer)."

Police Chief Inspector Exequiel Cautiver, a training director at a police school in nearby Laguna province, was immediately arrested by his superiors. He later admitted that the kidnapping was masterminded by a former vice mayor of Dasmarinas town in Cavite.

Former vice mayor Victor Carungcong was arrested in a follow-up operation, Espina said.

Two more suspects, including another policeman, were still at large, he said.

Espina said Carungcong planned the kidnapping to get rid of Canete, a business rival.

Police investigators have found that Carungcong had been trying to wrest control of a business owned by Canete's family. Prior to the kidnapping, the suspect even fired his gun at the establishment when security guards did not allow him to enter. (dpa)