When Christopher Reuther was fatally punched in a Nanakuli beach parking lot last year, the world lost a brilliant young man whose family has been devastated by his death, Reuther's mother told the court in emotional testimony yesterday morning.

"Chris loved life and living, and every day to him was an adventure," Judy Wilson said.

She urged Circuit Judge Michael Town to sentence Reuther's killer, Less Allen Schnabel Jr., to 20 years in prison, the maximum sentence.

"My son's wonderful smile, his sparkling eyes, his loving and enthusiastic personality and his fantastic brain are all gone, lost on a beach in Hawai'i through no fault of his own," she said.

"My son should not have died and he certainly should not have died in this way," said Wilson, adding that she has delayed treatment for invasive breast cancer so that she could travel here from North Carolina to testify at Schnabel's sentencing.

Reuther was "a firm believer in fairness and justice, which is why I would ask the court to honor his ideals and memory by giving his assailant the maximum 20 years prison sentence," Wilson said.

Town agreed with her and said he was imposing the maximum sentence on Reuther "without a lot of hesitation."

"Someone's life is gone," Town said.

The attack on Reuther, 34, "was unprovoked, it was tragic and I can't understand it," the judge said.

Schnabel also addressed the court. "I would like to apologize for what I have done, for punching Christopher Reuther and for the fact that he died," he said.

Schnabel said he allowed crystal methamphetamine to "take over my decisions."

"This whole thing has been like a dream," he continued. "Drugs killed my awareness of life."

The hearing began with testimony from another victim of Schnabel's, Cameron Gernhard, who was assaulted by Schnabel on a Nanakuli beach in 2002, according to court records.

Gernhard said he was at a friend's birthday party and was walking back to his car when he was punched in the left temple and then kicked while he was on the ground.

Schnabel was convicted of assault in Family Court but the records of the case were sealed because he was a juvenile at the time.

Defense lawyer Debra Loy said yesterday that Schnabel was innocent of the offense.

Loy told Town that Schnabel has turned his life around and asked that he be sentenced to probation.

"He is not a monster," she said.

Reuther's death, she said, was caused by "cultural differences, drugs, anger and miscommunication."

But Schnabel "is a good man now," she said, working full time in a construction job, with a fiancee and 3-year-old son.

"I find Less to be an honorable person," Loy said.

Deputy Prosecuting Attorney Darrell Wong told the judge that Schnabel deserved the maximum penalty available, calling the case "a story about choices and accountability."

"This is a serious crime, your honor," Wong said.

"Christopher Reuther is never coming back. He's gone."

Reuther was punched in the head after he took Schnabel's photograph in the parking lot of Zablan Beach Park near midnight on April 22, 2007. He died at Hawai'i Medical Center-East on April 24.

Reuther came to the Islands to visit the William S. Richardson School of Law at the University of Hawai'i. An honors graduate from the University of North Carolina who had been working as a magazine photojournalist, Reuther had been offered a partial scholarship to enroll in the environmental law program here.

Prosecution witnesses in the manslaughter trial testified that Schnabel punched Reuther once in the side of the head and said the attack was unprovoked.

Reuther fell senseless to the ground and died two days later of a lacerated artery at the base of his brain.

Various witnesses said Schnabel was angered after Reuther unexpectedly took a photograph of him in the parking lot and twice told Reuther to "get the ---- out of here."

Reuther was an organ donor, and Wilson said yesterday that six people have benefited from his posthumous generosity.

"Four people in Hawai'i, one in Minnesota and one in New Jersey are living a better quality of life because of his generosity," Wilson said.