Campus Killer: Inside Tragic Case of College Student, 21, Murdered by Her On-Again, Off-Again Lover (2024)

After several days spent with her parents setting up her new off-campus apartment at the University of Mississippi, Ally Kostial was excited for the upcoming year, when she'd be a senior. She would head up the student golf and running clubs she'd founded, and also teach yoga and Pilates classes while also finishing her degree as a marketing major.

"That goodbye was so hard," Ally's mom, Cindy, explained in a statement of that July 17, 2019 farewell. "We didn't know it would be our last one."

Three days later, Ally's body was found at a lakeside camp site near the Oxford school. Her classmate and sometime boyfriend, Brandon Theesfeld, 24, is now headed to prison for life, after pleading guilty on Aug. 27 in to an amended charge of first-degree murder, sparing him the death penalty.

As assistant District Attorney Mickey Mallette read in a detailed account of the evidence, Theesfeld drove Ally to Sardis Lake in the early hours of July 20, 2019, shot her multiple times and left her to die beside a picnic table.

"Our lives have been forever altered and shattered," Cindy said in a statement that Mallette read next. "'Her absence haunts us every day."

Growing up in St. Louis, Ally was a cheerleader, a track runner and a member of the honor society who "was always so positive," Casey Hendrickson, Ally's friend since sixth grade, has told PEOPLE. At the University of Mississippi, she fell hard for Theesfeld, a native of Fort Worth, Texas, during freshman year.

Ally's attachment to Theesfeld confused some of her friends, who say he treated her poorly.

"He'd say hurtful, degrading things," one friend tells PEOPLE in this week's issue, on newsstands Friday.

Says Theesfeld's defense attorney Tony Farese: "She liked him more than he liked her, is the easiest way to say it."

For more on Ally Kostial's tragic death at the hands of a fellow University of Mississippi student, subscribe now to PEOPLE or pick up the most recent issue, on newsstands Friday.

On April 12, 2019, according to the prosecutor's evidence read in court, Ally told Theesfeld she might be pregnant. Two days later, she sent him a photo of an inconclusive home pregnancy test, saying she wanted to talk. Theesfeld replied that becoming a father at his age of 22 "would ruin his life," Mallette said in court. Evidence shows he searched the internet for abortion services and abortion pills.

Over the next three months, their communication was "exclusively electronic," Mallette told the court, and in July, Ally's repeated requests to meet became more urgent "to discuss the issue of whether or not she was pregnant."

On July 12, Theesfeld told Ally that there was no need to meet, and he travelled from Oxford to his father's home in Texas to retrieve his dad's .40-caliber Glock 22.

He posted a picture of it on social media with the caption "Finally taking my baby back to Oxford." He'd search the internet for silencers, and how serial killer Ted Bundy lured his victims.

Back in Oxford on July 17, the same day Ally was seeing her parents off, Theesfeld — for the first time since their last sexual encounter in April — sent Ally a message, the prosector said in court, asking to meet.

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He picked her up at her apartment, drove for Sardis Lake and, while in back of her, shot her 12 times. It was later revealed she was not pregnant.

Theesfeld was arrested on Monday, July 22, at a gas station in Memphis, Tenn., with the murder weapon in his truck.

Back at his Oxford apartment, authorities found a two-page handwritten letter signed by Theesfeld: "Dear Mom and Dad, I am 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 demons. I know I'm going to get caught."

While a mental evaluation after his arrest found Theesfeld was sane when he murdered Ally, his attorney says that Theesfeld was "drunk and doped up" — under the influence of cocaine — that night at the lake.

It was, to Ally's parents, no excuse. "He shot her several times. She hurt and she bled and he left her," Keith Kostial told the court through his statement last month. "Few people in life will ever feel the pain that we have experienced, and it will never go away"