Belcher's mother, Cheryl Shepherd, had been living with the Kansas City Chiefs linebacker and 22-year-old Kasandra Perkins to help care for their three-month-old daughter, Zoey, and was at the couple's home Saturday morning when Perkins was shot.
"That's my son, and I love him," Shepherd said in a brief telephone conversation Wednesday. "She's my daughter-in-law, just like my daughter."
Shepherd declined to say anything more about her son.
Belcher shot Perkins at their Kansas City home then drove with a handgun to Arrowhead Stadium, where he thanked Chiefs general manager Scott Pioli and coach Romeo Crennel for all they had done for him. The men tried to persuade Belcher to put the gun down, but when police arrived, Belcher moved behind a vehicle in the practice facility's parking lot, knelt down and shot himself in the head, police said.
Shepherd, 54, said she was not happy about the release Wednesday of recordings of the emergency phone call she made Saturday after Perkins was shot.
"I just got a phone call that they did that, and I don't appreciate it," she said. "Right now I don't want to talk about it."
In the emergency call, Shepherd begs Perkins to "stay with me" while frantically asking for an ambulance. She tells the dispatcher that Perkins is "still breathing but please hurry. ... They were arguing, please hurry."
Shepherd also told dispatchers that Perkins was bleeding, "just barely" awake and that it looked as though she was wounded in the back. She said Perkins moved when she spoke to her.
When a police dispatcher asked about Belcher, Shepherd says only: "He left."
Police arrived at the home about 7:50 a.m. They said in an incident report that they found Perkins' body on the floor of the master bathroom. She had been shot multiple times.
Shepherd, who has temporary custody of the couple's baby, said she and Perkins were very close.
"She was a lovely, beautiful young woman. And we had a beautiful relationship," Shepherd said.
The estate or guardian of Belcher's 3-month-old daughter will receive more than $1 million under terms of the NFL's collective-bargaining agreement.
The child stands to receive $108,000 annually over the next four years, $48,000 in the fifth year and then $52,000 each year until age 18. She'll continue to receive that amount until age 23 if she attends college.
The beneficiary of Belcher, who was in his fourth season, also will receive $600,000 in life insurance, plus $200,000 for each credited season. There is also $100,000 in a retirement account that will go to his beneficiary or estate.
Players' beneficiaries are kept confidential.
Shepherd said family members have been helping her a great deal since the shootings, but that she had trouble eating and sleeping while working on her son's funeral arrangements.
Mourners, including several Chiefs players, attended an hourlong private memorial service for Belcher on Wednesday in Kansas City. Retired Chiefs Hall of Famer Bobby Bell said afterward that Pioli and Belcher's uncle spoke during the service. He said it was "rough" on Pioli.
"This is a sad situation," Bell said. "You never want to be put under those situations. Never. It's not good. You don't want to see things like that. I don't know how they got through it."
AP Sports Writer Dave Skretta and AP Writer Heather Hollingsworth contributed to this report.