A man convicted in 2000 of killing an 11-year-old boy and throwing him into a Littleton trash bin has died under "suspicious circumstances" at Sterling Correctional Facility, officials said.Lyle Brent White was pronounced dead at Denver Health Medical Center on Thursday, Chief Deputy Coroner Michelle Weiss-Samaras told the Denver Post.White, 40, was serving a life sentence in the Sterling Correctional Facility for the January 2000 slaying of Centennial Elementary School fifth-grader Antonio Davalos, the newspaper reported. White's body was returned to Logan County, where the prison is located, for an autopsy scheduled later Saturday.Katherine Sanguinetti, spokeswoman for the Colorado Department of Corrections, said another inmate at Sterling has been placed in segregation, according to the Post. An investigation by the Inspector General's Office is underway.The inmate had been in the prison's high-security section.White was the second inmate killed at Sterling in five days, the newspaper reported. An inmate was killed in a minimum-security cell block on Nov. 25, Sanguinetti said.Antonio was strangled in his grandmother's Littleton townhome, stuffed in a duffel bag and thrown in a Jefferson County strip-mall trash bin not far from Columbine High School, the Post reported.During his trial, White blamed the murder on his 28-year-old brother, who has Downs Syndrome. White said he heard a crash and saw his brother standing at the bottom of the stairs with his foot on Antonio's throat. White claimed he wanted to protect his brother.White had testified that he and his brother drove around town and to the mountains, and ate McDonald's food as the boy lay in the back of his van in the bag.