Prosecutors pursuing a third trial against a federal agent for a fatal 2011 shooting in a Waikiki McDonald’s restaurant plan to take their quest to the U.S. Supreme Court.

They want the high court to weigh in on whether they can try U.S. State Department Special Agent Christopher Deedy again on a manslaughter charge, Brooks Baehr, spokesman for the Honolulu prosecuting attorney’s office, said today.

Prosecutors must now turn to the Supreme Court after the 9th U.S. Circuit of Appeals rejected last week a request for a wider panel of judges to hear the case. A 2013 murder trial for Deedy ended in a hung jury. A second jury in 2014 acquitted him of murder but deadlocked on manslaughter.

An appeals court panel ruled that if prosecutors want to try Deedy a third time, it can only be for assault and not manslaughter.

“Our office will continue to pursue a favorable ruling from the U.S. Supreme Court,” Baehr said.

Deedy’s attorneys also asked for an expanded panel of judges to review the ruling — but for different reasons. They don’t want Deedy to face a third trial for any charge.

His attorneys have argued that a third trial would violate the double jeopardy clause of the U.S. constitution. The Hawaii Supreme Court ruled that a retrial wouldn’t violate his double jeopardy rights. Deedy then turned to the federal court system to prevent the state from trying him a third time.

Deedy had been in Honolulu providing security for the 2011 Asia-Pacific Economic Cooperation summit. After bar-hopping with friends on his first night in Waikiki, Deedy fatally shot Elderts during an altercation in a McDonald’s.

Deedy testified at two trials that he was protecting others from the aggressive Elderts. Prosecutors have said Deedy was drunk, inexperienced and fueled by warnings from a fellow agent that Hawaii locals are hostile toward federal workers and outsiders.

Thomas Otake, an attorney representing Deedy, did not immediately respond to email and phone messages today seeking comment.

Prosecutors’ insistence on a third trial is “absurd,” said Kenneth Lawson, a law instructor at the University of Hawaii law school.

“You had your shot. If you wanted to charge him with assault, you should have done it from the beginning,” he said. “Most prosecutors indict with lesser-included offenses in case a jury finds a defendant not guilty of murder.”