The Upstate man who was serving time after prosecutors said he confessed to killing his wife and putting her body in a 55-gallon oil drum has died in prison, according to the South Carolina Department of Corrections. Lee Mikeal Cawthon, 45, was sentenced in 2018 to 40 years in prison plus five years for possession of a weapon during the commission of a violent crime.He was serving his time at Lee Correctional Institution in Bishopville where authorities said he was found dead Tuesday."The SCDC Office of Investigations and Intelligence and S.C. Law Enforcement Division are investigating the death as a suspected suicide," a news release from the state Department of Corrections said. An autopsy will be done to determine the cause of death. Story below from 2018 details Cawthon's confession:An open marriage led to a woman’s murder, a bizarre post-death ritual, a cover-up and ultimately her 42-year-old husband's conviction, according to prosecutors.(Archive video above after Lee Cawthon's arrest)A news release from Solicitor David Wagner described the events leading up to and following the murder of Rebecca Cawthon by her husband, Lee Mikeal Cawthon. According to the release, Lee Cawthon married Rebecca when she was 17 years old, after he divorced his first wife. The Cawthons had an open marriage in which they invited one or more sexual partners to join them, the release said. Despite the open marriage, the couple was virtually inseparable, often choosing occupations where they could work together to minimize their time apart, the release said. The release said the marriage had become strained as Rebecca Cawthon became more independent, had started a new job and the couple had invited a male partner into the relationship for the first time. The couple had been drinking with the male partner on Easter Sunday 2017 when Lee Cawthon assaulted his wife after an argument. Rebecca Cawthon went to Oconee Memorial Hospital, where she told a doctor she had fallen down stairs. After she was released, she sent photos of her injuries to friends and was comforted by the male partner that the release said she and her husband “shared.” The release said Rebecca Cawthon went back to the home the next day to collect her belongings and to tell her husband she wanted a divorce. Lee Cawthon became enraged and shot her multiple times, prosecutors said. The release said that after Lee Cawthon was sure his wife was dead, he placed coins on her eyes “for the boatman,” referring to a death ritual from Greek mythology wherein coins are placed on the eyes of the dead to ensure the passage over the River Styx, which divides the living and the dead. Investigators said Lee Cawthon cleaned up the crime scene and drove to Clayton, Georgia. He used his dead wife’s phone to send text messages to her relatives to cover up her disappearance, the release said. When Cawthon returned to Oconee County, he put his wife’s body in a 55-gallon oil drum and put it in a grease pit under a tractor, investigators said. Prosecutors said Cawthon then went to Oklahoma to visit someone named “Hamster” whom the couple had met in the online game, "World of Warcraft."The Oconee County Sheriff’s Office had begun investigating the disappearance of Rebecca Cawthon when Lee Cawthon returned home, went to the Sheriff’s Office and confessed to killing his wife. Cawthon then led investigators to Rebecca Cawthon’s decomposed body and to the murder weapon, which was in his vehicle.