Kenneth Franklin Gadson, a former Marine working as a civilian at Kadena Air Base, Okinawa, has been been charged with murder and rape resulting in death in the slaying of a 20-year-old local woman. (Screenshot from NNN)

Kenneth Franklin Gadson, a former Marine working as a civilian at Kadena Air Base, Okinawa, has been been charged with murder and rape resulting in death in the slaying of a 20-year-old local woman. (Screenshot from NNN)

Rina Shimabukuro is seen in an image from a Fuji Television broadcast. Kenneth Franklin Gadson, a former Marine working as a civilian at Kaden Air Base, Okinawa, has been charged with murder and rape resulting in death in the slaying of the 20-year-old local woman. (Screenshot from Fuji TV)

CAMP FOSTER, Okinawa — A former U.S. base worker will admit to a charge of rape leading to the death of a Japanese woman last year, a new development in the case that rocked the tiny island prefecture and led to a surge in anti-American sentiment.

Kenneth Franklin Gadson, a former Marine who worked as a civilian at a Kadena Air Base cable and internet company, said through his attorneys that he killed Rina Shimabukuro, 20, while attempting to rape her, according to Naha District Court documents filed Friday.

“We do not dispute the charge of rape resulting in death,” the documents said, adding that Gadson admits to striking Shimabukuro on the head from behind while attempting to rape her. “As a result, the victim died … The defendant had no murderous intent, therefore we dispute the charge of murder.”

Gadson, who also goes by his Japanese wife’s surname of Shinzato, has maintained that he did not actually rape Shimabukuro.

However, under Japanese law, attempted and actual rape resulting in death fall under the same charge.

“I did not have the intention of killing the victim,” Gadson told Stars and Stripes in a statement in June. “Furthermore, I did not rape her. I will state the details of the case in court.”

Gadson’s first pretrial conference is scheduled for March 10. The trial is expected to begin sometime around June.

The admission’s timing surprised some legal scholars, since prosecutors haven’t yet presented evidence in court. It was most likely an attempt at a lesser sentence by showing remorse, which is considered very important in the Japanese justice system.

“Generally speaking, if you do not admit anything while there is obvious evidence, the attitude is seen as atrocious, with no remorse; thereby, the sentence tends to be longer,” said Tetsumi Takara, a law professor at the University of the Ryukyus.

Takara said the death penalty cannot be discounted in this case, though it is rarely handed down in cases involving a single death.

“There is a possibility that he chose this route for a lesser sentence by giving a good impression to [the civilian] judges (similar to an American jury),” Takara said. “Having said that, it is still strange to admit the charge before trial.”

Gadson was charged with murder and rape resulting in death by Japanese prosecutors two months after Shimabukuro disappeared on April 28. He was also charged with the illegal disposal of a body.

Following interrogation, he took police to the wooded area where her remains were found. He confessed to the crime, police said, but his lawyers argued he was questioned while under the influence of sleeping pills after a suicide attempt.

The brutal slaying shocked the Japanese, triggering anti-American protests on the island, where half of about 50,000 U.S. troops in Japan are based.

Former President Barack Obama was forced to apologize for the crime during his visit to Japan in May, following a strong rebuke from Prime Minister Shinzo Abe.

The Gadson case has continued to provoke public discourse, as his attorneys have continued to leak details that seem right out of a true crime-based novel.

They have said Gadson suffers from visual and auditory hallucinations and that while he hated his “cognitively limited” mother, they were co-dependent on each other. The statements contrast with Gadson’s image as an honorably discharged U.S. Marine and a family man married to a local Okinawan woman, who had just had a baby.

Gadson’s defense team has said it plans to request a mental-health evaluation before trial. Japan’s penal code includes provisions for insanity and diminished capacity, which could lead to Gadson receiving a reduction in punishment, or being committed to a mental hospital.

burke.matt@stripes.comsumida.chiyomi@stripes.com