A Marine was arrested in Okinawa over the weekend on suspicion of robbing and murdering a Japanese woman, a grave case that prompted the Japanese government to file a formal protest with the United States.

Japan’s public broadcaster NHK reported that police identified the suspect as Lance Cpl. Devin Jacob Ballard. He is assigned to Marine Corps Air Station Futenma on the island.

The Marine Corps confirmed that the arrested suspect was assigned to III Marine Expeditionary Force. Japanese police identified the victim as Yagi Anna, 39.

According to authorities, Anna was killed by suffocation at a hotel in Naha City, the capital of the prefecture. The killing occurred during the early hours of Oct. 3.

Authorities also said Anna’s wallet and backpack were stolen. Ballard, 20, was arrested at 1 a.m. local time Sunday, according to police.

Police said security camera footage showed a man entering the hotel with Anna. The footage then showed the man leaving the hotel alone.

The killing and subsequent arrest drew reactions from senior Japanese officials. Japanese Prime Minister Sanae Takaichi publicly addressed the government’s demands following the incident.

Takaichi said the Japanese government “has strongly requested their full cooperation in the investigation, stricter discipline among U.S. military personnel, and thorough measures to prevent the recurrence of such incidents and accidents.”

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The incident also led the Japanese government to file a formal protest with the United States. The arrest comes as local Japanese authorities continue handling the investigation.

III Marine Expeditionary Force issued a statement on social media acknowledging the allegations and its cooperation with Japanese authorities. The command also offered condolences to Anna’s family and friends.

The command said it is “actively cooperating with Japanese authorities, in response to allegations of serious criminal actions by a Marine assigned to the III Marine Expeditionary Force. We extend our deepest condolences to the victim’s family and friends.”

III Marine Expeditionary Force said the Marine Corps expects its personnel to meet the service’s standards of conduct. It also confirmed that the Marine remained in Japanese custody as the investigation moved forward.

“The Marine Corps takes these allegations very seriously and expects every Marine to adhere to the highest standards of behavior. The Marine is in custody of local authorities while investigations proceed,” the statement continued.

The Marine statement did not provide additional details about the allegations, evidence, or ongoing investigative process. “There’s no further information to release at this time.”

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The U.S. Embassy in Tokyo released a similar statement concerning the service member’s detention and the death of the Japanese national. The embassy said it was working with local officials and Japan’s government.

The embassy said it is “aware that a US service member is in custody following the death of a Japanese national in Okinawa,” and added that it is in “communication and cooperating with” the relevant Japanese authorities.

Thousands of Marines are stationed in Okinawa, placing the American military presence near communities across the island. Naha City has already been a focus of coordinated patrol activity involving Japanese and American military police.

In April 2025, Japanese and American military police began conducting joint patrols around Naha City. Those patrols were started in response to a series of incidents involving American service members.

The latest case now places a Marine in the custody of local authorities while the investigation proceeds. Japanese officials have demanded cooperation, stricter discipline among U.S. military personnel, and measures intended to prevent similar incidents and accidents.