KANEOHE BAY, Hawaii - A U.S. Marine will spend 30 days in jail and have his rank reduced for punching and kicking a fellow Marine who killed himself shortly afterward, as a judge said she found no evidence the abuse led to the suicide.

Lance Cpl. Jacob Jacoby, who pleaded guilty to assault, acknowledged he punched and kicked Lance Cpl. Harry Lew out of anger and frustration that Lew repeatedly fell asleep while on watch for Taliban fighters in Afghanistan.

Jacoby, one of three Marines accused of hazing, told a judge he wanted to talk to Lew to find out why he kept falling asleep but got angry when Lew spoke to him in a disrespectful manner.

Squad members and officers had tried different methods to get Lew to stay awake, including referring him up the chain of command for discipline and taking him off patrols so he could get more rest.

But on Lew's last night, when he fell asleep again, those efforts escalated into alleged acts of violence and humiliation, according to the charges. The Marines were accused of punching and kicking him, making him do push-ups and pouring sand in his face.

A central issue in the case has been whether the Marines intended to humiliate and harm Lew or discipline him.

Before Lew shot himself in April with his machine-gun, he scrawled a note on his arm: "May hate me now, but in the long run this was the right choice I'm sorry my mom deserves the truth."

Lew's father, Allen Lew, said he doesn't understand how Marines could do the things they did to their own.

"My son died -- I have only one son," he said.

Navy Capt. Carrie Stephens, the judge in Jacoby's special court-martial, said she found no evidence that Jacoby's abuse caused Lew to kill himself. She said she didn't take the suicide into account when determining the sentence.

As part of the plea deal, prosecutors withdrew charges that Jacoby humiliated and threatened Lew.

Before sentencing, Jacoby said he was sorry and that he wanted to take responsibility for his actions.

"I allowed my emotions and frustrations to get the best of me, and acted out against a fellow Marine," Jacoby said.

Navy Lt. John Battisi, Jacoby's attorney, asked the judge to keep in mind the circumstances the Marines were in, and that the chain of command hadn't addressed Lew's sleeping problem.

Two other Marines are accused in the case. Sgt. Benjamin Johns, the leader of the squad the Marines belonged to, and Lance Cpl. Carlos Orozco III will have their own separate courts-martial.

The 21-year-old Lew was a nephew of U.S. Rep. Judy Chu, who attended the hearing. "I want to make sure that there is justice for Harry. And I want to support these brave persons, his parents," she told reporters beforehand.