KANSAS CITY, Mo. — Kansas City Chiefs linebacker Jovan Belcher on Saturday morning shot and killed his girlfriend before going to Arrowhead Stadium and fatally shooting himself as team personnel tried to stop him, police said.

Belcher attended the University of Maine, where he played football from 2005-2008 and was a first-team All-American as a senior before he graduated in 2009.

Police Capt. David Lindaman said Belcher, 25, and his girlfriend, Kasandra Perkins, 22, got into an argument around 7 a.m. CST at their home in the 5400 block of Crysler Avenue in Kansas City. Around 7:50 a.m., Lindaman said, Belcher shot his girlfriend multiple times. She was taken to a hospital, where she was pronounced dead.

Lindaman said Belcher’s mother, who was visiting the couple and their 3-month-old daughter, witnessed the shooting and was being interviewed by police.

Belcher left the scene on Crysler and went to the Chiefs’ practice facility at Arrowhead, police said.

Police were called to the stadium around 8:10 a.m. When Belcher arrived there, he encountered General Manager Scott Pioli, Coach Romeo Crennel and other team personnel. Police said Chiefs staff attempted to keep Belcher from committing additional acts of violence.

“As officers pulled up and were getting ready to get out of their car, they heard a gunshot,” Kansas City police spokesman Darin Snapp said.

Snapp said Belcher shot himself in the head in front of Crennel and Pioli.

“He was not threatening the employees at all,” Snapp said. “He was just talking to them and thanking them for everything they had done for him.”

“We can confirm that there was an incident at Arrowhead earlier this morning,” the Chiefs said in a statement. “We are cooperating with authorities in their investigation.”

UMaine athletics on Saturday afternoon issued the following statement by Cosgrove:

“His [Belcher’s] move to the NFL was in keeping with his dreams,” says Cosgrove. “This is an indescribably horrible tragedy. At this difficult time, our thoughts and prayers are with Jovan, Kasandra and their families.”

The Kansas City Chiefs host the Carolina Panthers on Sunday at Arrowhead Stadium. The Charlotte Observer reported that the NFL informed the Panthers to leave on their team charter plane as scheduled Saturday.

Earlier this year, Belcher signed a one-year deal worth just under $2 million. He had started 10 of 11 games at inside linebacker for the Chiefs this season and was in his third season as a full-time starter, fourth overall in the NFL. A 6-foot-2-inch, 228-pound outside linebacker, he had been in on 38 tackles this season.

During his four-year career, Belcher participated in 59 games, starting 44. He logged 257 career tackles and forced one fumble.

Belcher was a star player at UMaine, where he was honored as the Colonial Athletic Association Defensive Player of the Year in 2008. He helped coach Jack Cosgrove’s Black Bears earn a spot in the NCAA Football Championship Subdivision playoffs.

As a senior, he was the runner-up for the Buck Buchanan Award presented to the best defensive player at the FCS level. He made 98 tackles, including 7½ sacks, in 2008.

Belcher, who earned a degree in child development and family relations, participated in the Male Athletes Against Violence initiative during his time at UMaine. He also mentored a local boy by doing different activities with him as part of his curriculum.

Friends, former teammates, family members, acquaintances and fans quickly began flooding Belcher’s Facebook page with messages of condolence upon learning of the tragedy on Saturday morning.

“Hard to believe, Jovan Belcher was as good a man as any,” posted former UMaine teammate Jacob Folz.

“I’m at a loss for words … lost a brother today and successor to the #9 tradition at Maine in Jovan Belcher … my thoughts are prayers are with both families involved,” was the post of former Black Bears defensive end and current UMaine strength and conditioning coach Matt King.

Judging from his final Facebook post, which came on Thursday, Belcher appeared to be in good spirits less than 48 hours before the apparent murder-suicide.

“Momma always said, Boy count ya Blessings!!” the post read.

According to a Bangor Daily News profile in 2008, Belcher’s senior year at UMaine, he was a student-athlete who was tenacious on the field but soft-spoken off it.

“He has a special ability to really jump into another gear and turn himself into a bit of a different being,” UMaine football coach Jack Cosgrove said of Belcher’s on-field personality at the time. “He plays with such passion and reckless abandon.”

The Sports Xchange, Kansas City Star writers Glenn Rice and Kevin Collison, and Bangor Daily News writer Pete Warner contributed to this report.