A high court Thursday upheld a lower court's ruling that sentenced a former U.S. military base worker to life in prison for the 2016 rape and murder of a 20-year-old woman in Okinawa.

The Naha branch of the Fukuoka High Court dismissed the appeal of 34-year-old Kenneth Franklin Shinzato, who admitted to the charges of rape resulting in death and abandoning the victim's body.

The defense counsel claimed he had no intent to kill and denied the murder charge.

According to the ruling, Shinzato attacked the woman on a road in Uruma, in central Okinawa, for the purpose of raping her on the night of April 28, 2016. He stabbed her in the neck with a knife and struck her on the head with a bar so she would not resist, resulting in her death.

The Naha District Court handed down the life sentence last December in line with prosecutors' demands.

In July, the Japanese and U.S. governments paid condolence money to the family of the woman instead of Shinzato, who said he lacked the means to pay, after the family sought compensation from Washington in March under the Japan-U.S. Status of Forces Agreement.

The United States has said the payment was made on a "voluntary and humanitarian" basis because the man was not an employee of the U.S. armed forces as defined by the agreement, according to the Defense Ministry in Tokyo.

Shinzato was a civilian working for an internet company on the Kadena Air Base in Okinawa Prefecture at the time of the crime, after serving as a U.S. Marine, according to his lawyer and the U.S. Defense Department.