(CBS News) Police say they don't yet know why Kansas City Chiefs linebacker Jovan Belcher killed his girlfriend and then killed himself.
The Kansas City Chiefs beat the Panthers 27-21 on Sunday, but the win couldn't compare to what their team had lost.
Linebacker Andy Studebaker told CBS Sports, "It's not easy. He was a friend, a brother."
On Saturday, police say 25-year-old Belcher shot and killed Kasandra Perkins, his girlfriend and the mother of his 3-month-old daughter, at their home. He then drove to the Chiefs practice facility. In the parking lot, he met and thanked the team's general manager Scott Pioli and head coach Romeo Crennel for all they had done.
In a 911 call, the caller said, "He's got a black pistol to his head, I see at least four guys standing trying to negotiate with him ... shots fired."
In front of the men, he shot himself.
Crennel said, "It's tough when circumstances happen, you can't undo them, and so you have to rely on each other, you have to rely on your family, your friends and rely on your faith."
Crennel decided to go ahead with Sunday's game. Crennel said it was his players that helped him decide to go ahead with the game, if -- for no other reason -- to take their minds off the tragedy for just a few hours.
There was a moment of silence for victims of domestic violence, but no official tribute to Belcher. Outside, fans had mixed feelings about how to honor the team's loss. Fan Sadie Johnson said, "He did commit murder and it was a suicide, ultimately, but with a murder, why would we salute a murderer?"
Friends say Belcher and his girlfriend separated briefly in November, but got together again at Thanksgiving. Those who were close to the linebacker are stunned by the shooting. Former Chiefs player Anthony Becht, who knew Belcher on and off the field, said, "He was a kid that was very positive and upbeat about where he was in his career and the opportunities that he was given -- he was very humble. It's unfortunate now that the only thing we will remember him for is for the tragic event and decisions that he did make."
Belcher was a standout player at the University of Maine. As an undrafted free agent, he worked hard enough to earn a starting position in Kansas City. His agent, Joe Linta, remembers meeting him for the first time. He recalled, "You just got the sense that this was a kid who was raised the right way. He was always polite, always articulate, always the model citizen."
Linta struggles to understand what happened Saturday. "You're worried and really even more than that is the numbness and shock you feel for someone that you know was incapable of something like this," he said. "In a way, it still hasn't sunk in yet really."
Chiefs players plan to start a fund for Belcher's daughter Zoey who is staying with a family member. James Brown, host of "The NFL Today" on CBS, said Belcher's mother currently has custody of the child.
Speaking to the puzzlement many have expressed in the wake of the murder-suicide, Brown said: "One of the things I'm learning from working with this whole domestic violence and prevention issue by way of the Verizon Foundation is oftentimes there's no discernible reason why, but there's some deep-seeded attitudes and clearly, there's going to be a lot more to come out of this and I'm very careful not to speculate right now because the police have not talked about a motive as well."
Asked about the decision to play on Sunday, Brown said there was a lot of discussion whether the game would go on. "The league left it up to the Kansas City Chiefs, specifically up to the coach. Romeo Crennel had his six team captains get together, take a poll of all of the players and unanimously they agreed to go forward with it. That was their way of coping with the situation. I really commend the organization also for having a moment of silence for domestic violence victims, while, of course, it happened with a very prominent football player and very well-respected sport, if you will, the issue is one that is well beyond football and one that needs to be addressed very seriously. "It's so sad because not only are two young people dead, but the collateral damage is so much more extensive," Brown said. "I've had an opportunity to interview a number of domestic violence survivors, and it's a very chilling story in terms of how a number of men especially, men are impacted as well too, but overwhelmingly women how there are some deep-seeded attitudes planted in young childhood, devaluing women and not providing men with the proper coping mechanisms. ... That's what needs to be addressed and hopefully I'm taking a small role in this, trying to engage a number of men in this process, so we can understand this and make a serious dent in this issue."