Crime 'Misogynistic' Ex-Ole Miss Student Admits to Murdering Ally Kostial After Thinking She Was Pregnant Brandon Theesfeld apologized in court for murdering Ally Kostial, but he did not reveal his motive By Chris Harris Chris Harris Twitter Chris Harris has been a senior true crime reporter for PEOPLE since late 2015. An award-winning journalist who has worked for Rolling Stone and MTV News, Chris enjoys prog rock, cycling, Marvel movies, IPAs, and roller coasters. People Editorial Guidelines Published on August 30, 2021 12:33 PM Share Tweet Pin Email Ally Kostial/ Facebook. More than two years after authorities found her body, Alexandria "'Ally" Kostial's accused murderer has confessed, pleading guilty last week to the 21-year-old University of Mississippi student's 2019 killing. On Friday, Brandon Theesfeld, 24, who was also an Ole Miss student, pleaded guilty to first-degree murder, acknowledging in court he drove Kostial to Sardis Lake in Oxford on July 20, 2019, before shooting her several times, a court clerk confirms to PEOPLE. Initially, Theesfeld was charged with capital murder. However, under the terms of last week's plea deal, the Texas man no longer faces a possible death sentence, and will instead spend the rest of his life in prison. While he did not say why he murdered her, Theesfeld apologized in court for Kostial's killing. U. Mississippi Student Is Found Dead 30 Miles from Campus — and Foul Play Is 'Apparent' "I am sincerely sorry for the pain I've caused while taking Ally from you," Theesfeld said, speaking directly to the victim's relatives, according to the Oxford Eagle, KMOV and KSDK. "My actions have forever changed your lives and my family's lives," he continued. "I wish I could take it all back but I can't. There is no excuse for my actions and I have asked God for forgiveness. I hope one day that you will find it in your heart to forgive me." Investigators learned that Kostial and Theesfeld met while attending the University of Mississippi. A former college housemate of Kostial's, Lauren Riddick, told PEOPLE in 2019 they "had a complicated relationship, an on-and-off one, but at no point did she say he was her boyfriend." On April 12, 2019, Kostial told Theesfeld she was concerned she might be pregnant. Two days later, according to the Eagle, she sent him a photo of an inconclusive home pregnancy test. Authorities learned that Kostial tried convincing Theesfeld to meet with her for months. But he wouldn't, the Eagle reports. Ole Miss Student Seen in Photos With Fellow Undergrad Suspected of Murdering Her Days before the murder, on July 12, 2019, Theesfeld texted Kostial, saying he did not want to meet with her, and that she should just terminate the possible pregnancy. Then, on July 18, Theesfeld texted Kostial, asking that they get together. On Friday, Theesfeld's defense attorney told reporters the young woman was not pregnant when she was killed. Brandon Theesfeld. Bruce Newman/The Oxford Eagle via AP Detectives used cell phone records to link Theesfeld to Kostial's killing, and arrested him days later in Tennessee. The Eagle reports that authorities found a two-page letter at Theesfeld's apartment after the killing, which he addressed to his family. It read, in part: "I'm not a good person. It is not your fault. Something in me just doesn't work. I've always had terrible thoughts. I've always had these feelings. I just kind of felt off. I think this is the end for me. I'm either going to prison or going to die. I know I'm going to get caught." Friends of Murdered Ole Miss Student Recall Her as 'Bright Light in Our Lives' During Friday's hearing, a statement from the victim's mother, Cindy Kostial, was read aloud in court. "I wish I could have kept her away from this evil, callous, scheming, ungrateful, sinister and violent and corrupt monster," Kostial's mother's statement read. "He had every opportunity to do good in the world, but he chose to do evil. Brandon, you belong in jail each day for the rest of your life for the heinous act you committed to such a sweet soul in Ally. Every time your cell door slams shut may it be a reminder for what you did and the life you took from us." In 2019, Kostial's friends spoke to PEOPLE, and said Theesfeld had little respect for women. Want to keep up with the latest crime coverage? Sign up for PEOPLE's free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases. "He'd use his money to get things, he'd have six girls around the table and he'd sit back and laugh at them, like a pig," one friend who wished to remain anonymous said. "He was super misogynistic."