Kent Carpenter, 73, was with his Filipina companion in a house in the coastal town of Sibulan, in Negros Oriental Province, on Sunday night when the masked men forced their way in.

One drew a gun and shot Carpenter in the head, killing him instantly, police said his companion told them. The men took a laptop, an unspecified amount of cash and a backpack before fleeing, national police spokesperson Col. Allen Rae Co told reporters.

This 2023 photo provided by Old Dominion University shows Professor Kent Carpenter. Photo by AP

Regional police spokesperson Lt. Col. Joem Malong told The Associated Press that Carpenter's companion sustained unspecified injuries and was being treated. Investigators were trying to determine the motive for the killing and identify the attackers.

Carpenter was a marine biologist who had worked as a lecturer at the Silliman University, in Dumaguete city, Negros Oriental, Malong said.