Police investigators said in a report obtained Tuesday by The Kansas City Star that Belcher -- who shot and killed Kasandra Perkins before taking his own life Dec. 1 -- had texted another woman saying he "would shoot" Perkins "if she didn't leave him alone."
Belcher, 25, shot and killed Perkins, the mother of his 3-month-old daughter, in the home they shared Dec. 1. He then drove to Arrowhead Stadium and killed himself with a different weapon in the parking lot.
The report indicated Belcher told a 22-year-old "secret girlfriend" that Perkins "knew exactly how to press his buttons and make him angry," adding that Perkins had "threatened to take all his money and his child if they split up."
The Star said the Belcher case file it had obtained held nearly 60 pages of witness interviews, recovered evidence and officer observations.
It contained evidence the relationship between the player and Perkins had become dangerously strained leading up to the murder-suicide.
For instance, investigators reported Chiefs Coach Romeo Crennel said Belcher blamed Perkins for missing a team meeting when she allegedly didn't come home the night before, adding the couple had "trust issues."
It also states Belcher's mother, Cheryl Shepard, had moved in with the couple, two weeks before their deaths. Shepard said her son and Perkins were having "relationship problems due to financial issues associated with Perkins' spending habits," and said the argument leading to the killings "was in regard to one or both of them going out, as in, to a club or partying."
Celebrity Families of 2014 [PHOTOS]