A 38-year-old Hilo man pleaded guilty Thursday to the shotgun slayings almost 4 1/2 years ago of his girlfriend and her mother.
Sean Ivan Masa Matsumoto entered guilty pleas to two counts of second-degree murder plus use of a firearm in the commission of a felony for the Feb. 11, 2013, shooting deaths of 45-year-old Rhonda Lynn Alohalani Ahu and her 74-year-old mother, Elaine Ahu, in their home on Leilani Street in Hilo’s Waiakea Houselots neighborhood.
In return for Matsumoto’s guilty plea, prosecutors dropped a first-degree murder charge, plus reckless endangering and three additional firearms offenses.
Hilo Circuit Judge Greg Nakamura ordered Matsumoto to appear for sentencing at 8 a.m. Sept. 6.
“He’s agreeing to a life sentence with (the possibility of) parole … and he’s agreeing to a mandatory minimum of 15 years,” Deputy Prosecutor Kelden Waltjen said. The Hawaii Paroling Authority will decide the length of time Matsumoto actually spends in prison.
Matsumoto had been scheduled for trial on Aug. 7. Had he been convicted of the first-degree murder charge, which was filed because there was more than one victim, Matsumoto would’ve faced a mandatory life sentence without the possibility of parole.
Matsumoto has been in custody without bail at Hawaii Community Correctional Center since his arrest at the crime scene. Police received numerous calls about the late-night shooting, including one from Matsumoto, “to report that he just shot two people in his residence,” according to court documents filed by police. Documents state Matsumoto told the 911 dispatcher “he felt that his ‘girlfriend was cheating’ on him, and that her ‘mother hated’ him.”
According to documents, an officer who arrived at the home at 11:27 p.m. that night found Matsumoto “pacing back and forth in the driveway” while talking on a cellphone. The officer reportedly found a spent .12-gauge shotgun shell on the ground next to Matsumoto.
Rhonda Ahu’s body was found in a recliner in the living room; Elaine Ahu’s body was on the floor in a bedroom. Both had been shot in the head and face. A .12-gauge Mossberg shotgun with a pistol grip handle was found on a love seat in the living room next to the front door, documents state.
Two children, Matsumoto’s and Rhonda Ahu’s then-6-year-old son, and Rhonda Ahu’s then-15-year-old daughter from a previous relationship, were in the home at the time of the shooting, police said, but neither were physically harmed.
Carol Luciano, Elaine Ahu’s sister, told the Tribune-Herald in 2013 that Rhonda Ahu’s daughter “saw everything.” She said Rhonda Ahu purchased the shotgun for Matsumoto — who had a domestic violence conviction and couldn’t legally buy or possess a firearm — shortly before the incident.
Email John Burnett at jburnett@hawaiitribune-herald.com.
