Roy Kawano quietly listened in court yesterday as Melvin Kumukau admitted to killing Kawano's father more than 31 years ago.

In a plea deal reached with the state attorney general's cold case unit, Kumukau, 58, pleaded guilty to one count of manslaughter and another of first-degree robbery and was sentenced to up to 20 years in prison by Circuit Judge Virginia Crandall.

Toshio Kawano was shot to death while working the evening of Sept. 26, 1977, at his small Mo'ili'ili bakery and liquor store in what Supervising Deputy Attorney General Christopher Young said was a botched robbery.

Under the plea deal, the state dismissed a murder charge against Kumukau in return for his guilty pleas to manslaughter and robbery.

Roy Kawano said he and other family members agreed with the deal after meeting with prosecutors and investigators in the case.

"We talked about different scenarios about what would happen and this was the best one," Kawano said.

"After all this time," he said, "we did have closure already."

A co-defendant, Aaron Meyer, 49, is scheduled to be tried this year. Court records show that Meyer has given conflicting statements that implicated himself and Kumukau.

Young said the crime was difficult to investigate because there were no eyewitnesses.

He said the case was revived after the state established its cold case unit in 2004 and used "additional information from a witness at the scene" to indict Meyer and Kumukau in December 2006.

Asked if the witness was Meyer, Young would not comment.

Young said Kumukau and Meyer intended to rob Kawano of a collection of samurai swords he kept at the store, but Kawano confronted the armed assailants with a firearm of his own.

In an exchange of gunfire, Kawano was shot twice and died two hours later.

Attorney General Mark Bennett said in a written statement that he was "glad we were able to bring a portion of this case to a close after so many years."

If Kumukau had gone to trial and been convicted, he would have faced a possible sentence of life with the chance of parole.

"Cold cases are very difficult to prosecute and, given the age of this case, a 20-year sentence is a just resolution," Bennett said.

The attorney general's office has successfully prosecuted one other homicide cold case, the 1992 killing of Pearl Harbor base cashier Ruben Gallegos by Jenaro Torres.

Torres was convicted in 2007 based largely on new testimony from a witness who said Torres admitted in 1997 that he had killed a man in a Hawai'i robbery.

That case, and the one against Kumukau, used witness testimony and did not rely on what Young called "CSI evidence" developed by using new scientific techniques such as DNA analysis in the examination of old evidence.

The only other cold case now pending in state courts does depend largely on DNA testing. In that case, developed by Honolulu Police Department detectives, Darnell Griffin is charged with the 1999 rape and murder of Evelyn Luka.