A Texas man diagnosed with bipolar disorder fatally stabbed his stepmother because he thought she was “gloating” about a win by the Dallas Cowboys, court papers show.

Pontrey O’Neal Jones, 20 — who stopped taking his meds two years ago — attacked Magdalena Ruiz inside their South Austin apartment following the Cowboys’ 26-20 victory over the Tampa Bay Buccaneers on Sunday, according to an arrest warrant affidavit obtained by the Austin American-Statesman.

Jones, who recently moved into the home, told investigators that Ruiz had disrespected his father and was gloating about the win prior to the attack.

Jones had initially decided to break his sister’s neck, according to the affidavit, but changed his mind and “developed a plan” against Ruiz, hiding a black-handled knife beneath a couch to attack her later, CBS Austin reported.

At about 10:40 p.m., just after the Cowboys locked up their 12th win of the season, Jones grabbed the knife and stabbed Ruiz several times before Jones’ father managed to intervene. Jones ran out of the apartment and was found about 10 minutes later, lying naked in the grass near an intersection where police eventually took him into custody.

“When informed the victim was deceased, Jones appeared relieved and advised he stabbed the victim multiple times under the belief that a single stab wound would fail to render death,” the affidavit reads, according to the Austin American-Statesman.

Jones, who told investigators he stopped taking his prescribed medications because they would “slow him down,” said he had previously planned to join the military, but the pressure was simply too high and that he had disappointed his siblings.

Jones has been charged with murder and remains jailed on $500,000 bond. It was unclear whether he has hired an attorney.

One of Ruiz’s longtime friends said she felt uncomfortable about Jones’ erratic behavior and the family’s new living situation.

“She said, ‘I guess I’ll let him come into my life and our apartment,’” Amanda Rivera told Fox Austin. “He was kind of scary because he was like one of those people like if you want to say something, he would attack you … I’m a little angry and pissed off about it because, why did he have to do that to her? Why did she have to leave with God? It wasn’t her time to leave. It wasn’t.”

A fundraising website has been established to offset Ruiz’s funeral costs.

“Maggie Ruiz was a loving, devoted wife and mother who worked extremely hard to make sure that her family was provided for and felt loved,” the site reads. “Her unexpected death leaves a deep hole in the hearts of all knew this kind soul. She leaves behind three children and a husband, her extended family, her many friends and neighbors, and a large community who enjoyed the sunshine she brought to all things.”