A former Marine recruit has pleaded guilty to first-degree murder in the death of 29-year-old Lauren Heike.

According to court documents, 25-year-old Zion Teasley stabbed Heike 15 times in the desert near Phoenix, Arizona, on April 28. His body was found on April 29 near a hiking trail close to her home. Investigators reported that Heike had been missing since April 27 when she failed to show up for work. An autopsy revealed she sustained multiple wounds to the upper body, with one wound measuring three inches deep and defensive injuries on her hands and forearms.

Teasley, who was on probation at the time of the attack after serving over a year in prison for armed robbery and other felonies, told police that Heike was “what I would want to look like.” In his diary entries, he described being depressed by seeing beautiful women because he could not be one of them.

Teasley had left the Marines shortly after boot camp and was fired from his job for aggression toward female coworkers. He also stole clothing matching what he described as “what I would want to look like.” A police report detailed Teasley’s statements about battling with his gender identity and sexuality, which he said conflicted with his Christian faith.

Lauren Heike’s family released a statement following the guilty plea: “After 3½ incredibly long and painful years, our family supports the State’s decision to enter into a plea agreement in Lauren’s case. … We are relieved knowing that he will never be released.” Teasley’s sentencing is scheduled for December 4.