A U.S. military serviceman killed his Japanese girlfriend and then himself at an apartment in Chatan, Okinawa, on Saturday morning, police said.

According to police, the 31-year-old serviceman, who is believed to be a member of the U.S. Marine Corps' 3rd Marine Division, and the woman, 44, were found lying in a 6th-floor apartment in the Kuwae area at around 7:30 a.m., Sankei Shimbun reported. Both had stab wounds. They were confirmed dead at the scene.

The woman's child, who was also in the apartment, was not hurt, police said. The child called a relative who contacted police.

Police said a bloodstained knife was found in the apartment near the man and believe he killed the woman, and then stabbed himself.

In a statement to media, U.S. Forces Japan said the Naval Criminal Investigative Service is working with local police to look into the deaths. The statement said: "This is an absolute tragedy and we are fully committed to supporting the investigation."

Meanwhile, Kyodo News reported that Japanese Vice Minister of Foreign Affairs Takeo Akiba called U.S. Ambassador William Hagerty, asking for cooperation with the investigation.

© Japan Today