A former U.S. Marine has been given life in prison for the rape and murder of a Japanese woman in April.

Kenneth Shinzato, 33, was working as a civilian contractor at Kadena Air Base in Okinawa, Japan, when he was charged with murder, rape, and illegal disposal of a body in the death of Rina Shimabukuro.

Shimabukuro, 20, went missing on April 28 after going for a walk. Her body was found three weeks later.

He pleaded guilty to rape resulting in death and abandoning of the body, but denied murder.

Shinzato was accused of hitting the woman in the head with a club, intending to rape her, and then stabbing her in the neck with a knife.

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Kenneth Shinzato, 32, left, a former Marine, has been given life in prison for the murder and rape of Rina Shimabukuro, 20, right

Shinzato, who was known as Kenneth Gadson before he took his Japanese wife's last name, revealed that he'd fantasized about suicide and rape for years, in statements transcribed by his lawyer and reported by Stars and Stripes.

Shinzato claims to have heard voices in his head since he was eight. He accused his foster mother of abuse, which she has denied, and says he fantasized of killing her.

The accused man says he had fantasies of abducting, restraining and raping women 'throughout my high school and adult years.'

Shinzato, who was known as Kenneth Gadson before he took his Japanese wife's last name, allegedly told investigators he drove around looking for a victim

In 2007, he claims he told Marine recruiters that he wanted to join the military primarily because he 'wanted to kill people.'

After joining, he relates various fantasies of killing himself.

'I remember thinking of how I could drown myself if I tired myself enough during the long range swim training,' he said.

'Out on the [shooting] range, I had the urge to go into the bushes and shoot at others and I could get shot.'

He reveals shocking details of the April crime in describing his version of the events.

'When she passed my car and I saw her more clearly, I heard the voice in my head tell me, 'It's her' and that she's the one that will fulfill my fantasy,' he said, speaking of the victim Shimabukuro.

'I wasn't 100 percent sure that she was the right one, but when I looked up, I saw a red, full moon and I just knew that that was a sign.'

Shinzato says he hit the woman over the head with a stick.

Dead: Rina Shimabukuro (pictured), 20, disappeared on the island of Okinawa, Japan, on April 28. Her body was found when Kenneth Shinzato, 32, a civilian worker at Kadena Air Base, gave police a location

Okinawa Prefecture Police investigate the site where the body of missing Rina Shimabukuro was found a day after U.S military base worker Kenneth Shinzato was arrested on May 20

'I intended to hit her with the stick and make her lose consciousness, then put her in the suitcase, take her to a hotel and then rape her,' he said.

The plan, he claims, was to release her alive after committing the vile crime, and didn't fear being caught because of the low reporting rate of sex crimes in Japan.

He says the headlights of an oncoming car forced him to drag her back from the road, accidentally hitting her head. As the woman tried to speak, he choked her in a panic, he said, and went to fetch the suitcase.

Believing the woman dead, he did not continue the assault, he claims.

Japanese prosecutors charged U.S. military contractor Kenneth Shinzato with the murder and rape of a 20-year-old woman on Okinawa. Pictured: Officials escort Shinzata to the prosecutor's office on May 20

Shinzato took the victim to a wooded location in Onna Village's Afuso district, where he dumped her body.

'When I disposed of her, I thought she may have said something,' the statements said. 'I thought that she may be alive, so I stabbed her with a knife to find out.

He says he stabbed the woman multiple times and she didn't make a sound.

'During the drive home, I was thinking that the effort required to play out my fantasy was more than I expected and the fatigue and stress was not worth it,' Shinzato said in the statements.

'I was expecting the police to come for me in a few days, but since they didn't I stopped worrying about it. I continued with my daily routine and went to work as usual. I didn't really think about the girl.'

Shinzato became a suspect after being spotted on surveillance footage buying salt and sprinkling it on his car, apparently in an attempt to get rid of blood stains, the Times reported.

He said in the statements that he wasn't afraid of being caught even after police began to question him, until the cops found a photo from the dead woman's Facebook page on his phone.

Shinzato eventually led investigator's to the location of the victim's body.

Shinzato is reportedly originally from New York. He joined the U.S. Marines and was deployed to Okinawa, where he met and married a Japanese woman, whose last name he took.

The case sparked outrage in Okinawa, where about 47,000 U.S. troops are stationed. The murder led to a bilateral pact limiting immunity from Japanese prosecution for civilian workers at American bases.

Prime Minister Shinzo Abe protested to then-President Obama during a state visit in May after the murder. Obama conveyed 'his sincerest condolences and deepest regrets.'