A Palmdale man pleaded guilty this week to killing his ex-wife and four others and then setting a Quartz Hill home on fire during a 2008 rampage.

Jae Shim, 45, pleaded guilty to the first-degree murders of his ex-wife, Jenny Young Park, 34; her daughter, Jamie, 13; her son, Justin, 11; a relative, Joseph Ciganek, 60 and the ex-wife’s boyfriend, Si Young Yoon, 34. Shim also pleaded guilty to arson of an inhabited structure.

Shim also admitted to the special circumstances of lying in wait and multiple murders and said that he personally used a Samurai sword and a baseball bat to stab and beat the victims to death on June 23, 2008. The plea before Superior Court Judge Larry Fidler was in exchange for prosecutors agreeing not to seek the death penalty against Shim, if he agrees to testify against co-defendant Steve Kwon. As part of his plea, Shim provided information that led authorities to the remains of Si Young Yoon who had been missing since the day of the murders. Yoon’s body was found in December 2014 in Mexico.

Shim is facing five consecutive life terms without the possibility of parole, when he returns for possible sentencing on May 5.

Kwon, 44, is awaiting trial on five counts of capital murder, one count of arson of an inhabited structure and one count of accessory after the fact. He returns to Superior Court for a pre-trial hearing on April 2. If convicted, Kwon faces life in prison without the possibility of parole.