Randal K. "Randy" Randrup was sentenced Tuesday to two years in prison and 10 years' probation for shooting his son eight times and throwing the body off a sea cliff.

The sentence, reached in a plea deal with prosecutors, counts time served since his arrest, meaning he will be released in February 2011.

The elder Randrup, 61, was originally charged with second-degree murder and firearms charges, but pleaded guilty in August to manslaughter for killing his son, Hans Christian "Chris" Randrup, 27, on Dec. 11, 2008. His nude body was found the next day, wrapped in a blanket at the bottom of a cliff at MacKenzie State Park in Puna.

The victim's mother, Lois Randrup, said there would be no justice if the plea agreement stood.

"The prosecution's handling of Chris' murder left me totally frustrated — no, disgusted — that they are treating it like he mattered so little. I am here to say that Chris mattered a lot," Lois Randrup said. "This evil man killed my son, his own son, in such an obscene manner."

Randy Randrup's lawyer, Francis Alcain, said the defendant acted after suffering escalating abuse from his son.

"On the surface, the relationship that Mr. Randrup had with his son, it appeared to be relatively calm. But little telltale signs were present," Alcain said. "Mr. Randrup would go to work with an injury one day that he didn't have before, or a cut, or a bruise, or pain and fear from a vicious kick over a dog. Little things. But the father-son relationship was marred by a pattern of abuse — violent, explosive abuse that continued to escalate in severity and concern."

Randy Randrup addressed the court, saying, "Your honor, this is the worst thing that could ever have happened. I'm so sorry it occurred. I could go on and on, but believe me, I never in my wildest dreams would imagine this occurring. It's so sad."

Circuit Judge Glenn Hara said he understood why the state allowed Randrup to enter into a plea bargain, because absent a confession the charge would have been difficult to prove.

"If your trial had proceeded without the confessions, there was a likelihood that without the confessions a jury might acquit you. You would have been completely absolved of this crime, and I think the prosecution took the route of deciding that half a loaf is better than none," Hara said.