CAMP FOSTER, Okinawa — Japanese prosecutors are looking at the case of an Okinawa-based Marine corporal who was arrested and charged with sexual assault, an incident that sparked a public protest and a strong statement from the prefectural governor.

Police said Tuesday that Cpl. Iian Christopher Tarver, 21, allegedly attacked a woman from behind at around 4:30 a.m. Saturday, leaving some bruises and scratches. The Marine was arrested and taken to the Naha police station after a witness reported screams.

Prosecutors investigating the charge of sexual assault with bodily injury will have about 20 days to decide whether to bring the case to trial, according to Japanese criminal law.

The Marine Corps issued a statement Tuesday saying it is cooperating with Naha authorities. All Marines are trained and briefed by superiors on proper off-duty behavior before being granted liberty leave, according to the service.

On Monday, the incident sparked a public protest outside the Marine Corps headquarters here and strong criticism from Okinawa Gov. Hirokazu Nakaima, who said the alleged crime “can never be forgiven,” according to Japanese media reports.