Jovan Belcher Update: Chiefs player texted he "would shoot" girlfriend "if she didn't leave him alone," police report says

(CBS) - About two months before Kansas City Chiefs linebacker Jovan Belcher shot Kasandra Perkins to death and then himself, he sent a text message to a secret girlfriend saying he "would shoot" Perkins "if she didn't leave him alone," the Kansas City Star reported Tuesday.

Pictures: NFL player kills girlfriend, then self, cops say

Police said the 25-year-old Belcher emptied his .40-caliber handgun into 22-year-old Perkins on Dec. 1 after an argument in their Missouri home. He then drove to his team's practice facility in Arrowhead Stadium and thanked general manager Scott Pioli and coach Romeo Crennel before killing himself in the parking lot.

Authorities have not released a motive for the murder-suicide, but the Star obtained a police report that outlined the couple's problems and how the Chiefs and Belcher's mother tried to help them, as well as detailing the events that led up to the shooting attack.

The 60-page report contained witness interviews, recovered evidence and officer observations, and talked about Belcher's text message to the woman who dismissed it as a joke. The file also said Belcher told the woman that Perkins, the mother of his 3-month-old daughter, "knew exactly how to press his buttons and make him angry" and had "threatened to take all his money and his child if they split up."

Crennel said he thought the couple had "trust issues" and Belcher's mother, Cheryl Shepherd, said she moved in with the couple because they were having "relationship problems due to financial issues associated with Perkins' spending habits," according to the report.

Shepherd said that before the killings, the couple argued "in regard to one or both of them going out as in to a club or partying," according to the report. Shepherd ran to the bedroom after hearing gunshots and saw Belcher kneeling next to Perkins' body, saying he was sorry. He then kissed her, their infant daughter Zoey and his mother before leaving for Arrowhead Stadium, the Star reported.

At the practice facility, Belcher ran into Pioli and told him he did "a bad thing to my girlfriend" and requested to meet with Crennel and linebackers coach Gary Gibbs. When the coaches tried to meet with Belcher and realized he had a gun, Crennel yelled, "You're taking the easy way out!"

As a police officer was approaching, Belcher made the sign of the cross on his chest and then shot himself in the head.

The case file also reported that police found multiple rounds were fired in the home and Perkins' body had 15 gunshot wounds.

Complete coverage of the Jovan Belcher case on Crimesider