Investigators returned from the  Philippines on Friday after looking into the recent shooting death  of a South Korean man, adding they have found key evidence to narrow down the suspects.

A 57-year-old South Korean, identified only by his surname Cho,  was shot to death by four unidentified, armed assailants on Sunday  at his house in Batangas, some 100km south of Manila.

The incident raised the number of South Koreans killed in the  Southeast Asian country to 11 this year. 

Police said they have identified the white SUV used by the  suspects, adding they have also secured CCTV footage of the car on  a highway around 4 kilometers from the scene.

Investigators will continue efforts to identify the license  plate on the car in cooperation with the authorities in the Philippines.

Police added they will expand the scope of the investigation as it could be a contract murder rather than just a robbery. (Yonhap)