A former U.S. Marine has admitted to killing a young woman whose body was found in bushes beside a road in central Okinawa, investigative sources said Friday.

Kenneth Franklin Shinzato, 32, told police on Thursday that he strangled and stabbed 20-year-old Rina Shimabukuro, an office worker from Uruma, the sources said. He was arrested on suspicion of dumping the victim’s body, a procedural step common in suspected murder cases.

An autopsy was unable to confirm the cause of death, police said Friday.

Shinzato, a civilian employee of U.S. Kadena Air Base, lives further south in the nearby town of Yonabaru with his wife and child. He was questioned on a voluntary basis on Monday.

Police say they found Shimabukuro’s body based on a statement Shinzato made on Thursday. He told police he dumped her in a wooded area after she stopped moving. Her body was found lying in undergrowth beside a road in the village of Onna, north of Uruma.

Over several days of voluntary questioning until his arrest Thursday, there were times when Shinzato could not be interrogated because he had taken a large amount of sleeping pills.

In the meantime, police have been unable to find Shimabukuro’s shoes and smartphone.

Investigative sources say police found a small amount of blood matching her DNA in Shinzato’s car. Since the amount was small, police suspect she was stabbed somewhere else.

Shimabukuro’s boyfriend was the last person to hear from her. He said she used Line to tell him around 8 p.m. on April 28 that she was going out for a walk. The boyfriend reported her missing the following day.

GPS data received from Shimabukuro’s smartphone shows her last confirmed location was an industrial area near her home in Uruma, the sources said.

Shinzato was a newcomer to Yonabaru, having moved there in March with his wife and baby.

Neighbors expressed shock.

“It looked like he was living a normal life. I don’t have a negative image of him,” one neighbor said.

Another, a 60-year-old woman, said: “I had been wondering what was going on because police cars have been parked nearby for the past few days.”

Okinawa hosts the bulk of U.S. military bases in Japan. Uruma hosts Camp Courtney and Camp McTureous.

Another violent crime against a Japanese is certain to fuel the already harsh anti-base sentiment in the prefecture.

Okinawa Gov. Takeshi Onaga, who has sparred with the central government on the contentious relocation plan for U.S. Marine Corps Air Station Futenma, expressed “extreme sorrow” over the incident on Thursday night.

“I don’t know what to do with this anger,” he said.

Tensions over the conduct of U.S. personnel have flared periodically over the years since the 1995 rape of a 12-year-old Okinawan schoolgirl by three U.S. servicemen prompted a wave of lasting public outrage.

The latest case again raised the question of how the civilian base worker will be processed under the Japan-U.S. Status of Forces Agreement, which defines the rules for handling U.S. military and other personnel.

Japanese prosecutors cannot indict members of U.S. forces or their “civilian component” if offenses are deemed to have been committed while on duty. The bilateral agreement says U.S. authorities in principle have the primary right to exercise jurisdiction in such cases.

Okinawa police say Shinzato will be categorized as a “civilian component” of the U.S. military. But since SOFA does not cover those who are off duty, Shinzato is expected to be tried under Japan’s legal system.