NEW YORK, Dhu-AlHijjah 24, 1436, October 08, 2015, SPA -- A Chinese immigrant who authorities said butchered five relatives with a meat cleaver, including four small children, will serve at least 125 years in prison after pleading guilty Wednesday to murder and manslaughter charges, according to AP. Mingdong Chen admitted that he killed his cousin's wife, 37-year-old Qiao Zhen Li, and her children, Linda, 9; Amy, 7; Kevin, 5; and William Zhou, 18 months; in October 2013. The 27-year-old showed no visible reaction as he entered his plea. Under a deal with prosecutors, Chen must serve at least 125 years in prison before becoming eligible for parole. Prosecutors said Li called her mother-in-law in China on the evening of Oct. 27, 2013, saying Chen was in the house with a knife and threatening the family. When the mother-in-law heard children crying in the background, she called other relatives in New York who rushed to the home in Brooklyn's Sunset Park neighborhood. By the time they arrived, the five relatives were dead and Chen was dripping in blood. Police said the family had been slaughtered, each of the five repeatedly stabbed and slashed in the throat and neck. Their bodies were found strewn about the house. Chen had been staying in their home for about a week before the killings, authorities said. When detectives questioned him, Chen told them he was jealous of the success of his fellow Chinese immigrants, police said. Relatives said he had been fired from different restaurant jobs. But exactly what set off Chen's rampage remains a mystery, one that left family members, prosecutors and the judge with a burning question. "The question is why he'd do these things," state Supreme Court Judge Vincent Del Giudice said. "It really doesn't much matter." Assistant District Attorney Mark Hale said prosecutors offered Chen the deal because it would spare Li's husband and other relatives from having "to relive the worst day of their lives." Hale said they also wanted to ensure that Chen would publicly admit to the killings. Li's husband was in court Wednesday but declined to comment. In 2014, a Brooklyn judge ruled that Chen was not competent to stand trial because he had exhibited signs of mental illness that made him incapable of being able to assist in his own defense. Chen's attorney, Danielle Eaddy, declined to comment. --SPA 03:31 LOCAL TIME 00:31 GMT www.spa.gov.sa/w