TOKYO (Reuters) – A Japanese court sentenced a former U.S. military base worker to life in prison on Friday for the rape and murder of a woman on the southern island of Okinawa, public broadcaster NHK reported.

The Naha District Court found Kenneth Franklin Shinzato, 33, guilty of killing 20-year-old Rina Shimabukuro in April last year, NHK said. A court spokesman told Reuters he was unable to immediately confirm the decision.

The case sparked anger on the island, where locals have long protested the presence of U.S. military bases that they say imposes a heavy burden on Okinawa.

Okinawa hosts around 50,000 U.S. nationals, including 30,000 military personnel and civilians employed at the bases.

In a bid to assuage locals, the United States last year agreed to limit legal protection and benefits to some U.S. civilian contractors working for the military in Japan under a Status of Forces Agreement (SOFA) that dates back to 1960.

SOFA exempts personnel from requiring visas while in Japan, and has been criticized because it has been used by the U.S. military to ship people home before Japanese police can capture them.

Other incidents involving U.S. personnel have stirred resentment among Okinawans. On Nov. 19, a local man was killed in road accident after his van collided with a car driven by a U.S. Marine suspected of driving under the influence of alcohol. The U.S. military responded by imposing a drinking ban for personnel in Japan on or off base.