Jovan Belcher fought with Kasandra Perkins when she came back late from Trey Songz R&B concert before murder-suicide

Jovan Belcher had argued with his girlfriend Kasandra Perkins after she came home late from an R&B concert the night before he shot her dead then drove to his team’s stadium and committed suicide in front of his coach and general manager, it has emerged.

The 25-year-old Kansas City Chiefs linebacker fatally shot 22-year-old Kasandra Perkins early on Saturday morning, then killed himself in the presence of Chiefs staff after first thanking them for everything they had done for him, police said.

Jovan Belcher and Kasandra Perkins lived together and three months ago had a baby together on September 11 – but a friend said they quarreled frequently, and added that they fought when Perkins arrived home at 1 a.m. after attending a performance by Trey Songz.

Authorities did not confirm a possible motive for the murder-suicide, which stunned the team and came one day before a home game against the Carolina Panthers. The NFL said the game would go on as scheduled.

Judging from pictures posted on Kasandra Perkins’ Facebook page, the young couple had appeared to be happy and in love following the birth of their first child.

“Jovan and Kasandra always seemed to be in love. In fact, when Kasandra got pregnant, she and Jovan were ecstatic. Ever since the baby was born in September, the two couldn’t have seemed happier together,” a member of the Perkins family told TMZ.

However, a friend told the Kansas City Star she had frequently seen them argue over the course of their relationship – though she had no reason to believe their fights had ever become violent.

On Friday night, she added, Belcher had confronted Perkins when she came home after watching R&B star Trey Songz perform in Kansas City.

Jovan Belcher’s agent Joe Linta told ESPN’s Adam Schefter: “I’m in shock. So out of character. He was the last person in the world you would expect to do this.”

“Jovan was a happy, proud father, with pictures of his baby on his Facebook page,” Joe Linta told SI.com’s Peter King in a phone call on Saturday afternoon.

“This is shocking. Something went crazy wrong, and we’ll probably never know what it is.”

“Never until four hours ago did I think Jovan was anything but a model citizen,” Joe Linta told Peter King.

“He came to my youth clinics in the offseason and worked with kids. He was a gracious, unselfish, hard-working, dedicated kid – very, very caring of some of the underprivileged kids who came to the clinics. I saw him in a real positive way.

“I never take on anyone as a client I wouldn’t be proud to take home and spend time with my wife and kids. Jovan was one of those type of people.

“There’s no word for this other than shocking. That’s all I can think of.”

Jovan Belcher was a native of West Babylon, New York, on Long Island, played college ball at Maine. He had played all four of his NFL seasons for the Chiefs and played in every game each year, including the 11 so far this season. His 2012 salary was $1,927,000, four times what he had earned for the previous year.

Before turning the gun on himself, Jovan Belcher thanked Chiefs general manager Scott Pioli and Romeo Crennel for all they had done for him, police spokesman Darin Snapp said.

Jovan Belcher’s mother had recently moved in with the couple, possibly to help with the baby, at their residence in Independence, Missouri about five miles away from the Arrowhead complex.

She called police just before 8 a.m. to report Perkins had been shot multiple times. Kasandra Perkins was transported to The University of Kansas hospital, where she died a short time later.