Kansas City Chiefs American football player Jovan Belcher has killed himself outside the team's main stadium.
Police said the 25-year-old first-team linebacker shot his girlfriend dead a few miles away, before driving to a training facility at Arrowhead Stadium.
He then shot himself in the car park in front of team officials.
The club confirmed the incident in a statement, adding: "We are co-operating with authorities in their investigation."
Kansas City police spokesman Darin Snapp told AP news agency that authorities were told early on Saturday that a woman had been shot five miles away from the Arrowhead complex.
The victim was later identified as Belcher's 22-year-old girlfriend, Kasandra Perkins.
The couple had a three-month-old daughter who was believed to have been in a nearby room at the time of the shooting. Belcher's mother had also been in the house and had called police.
According to local TV station KMBC 9, a friend of Kasandra Perkins said the couple had squabbled about an incident the previous night but there had been no evidence of any other problems between them.
Police were then called to the training facility, where they saw the player in a car holding a handgun to his head, talking to two Chiefs officials. They then heard a gunshot.
He had thanked the team's general manager and coach before shooting himself, police said.
In a statement, the Chiefs said the team would play its home game at Arrowhead against the Carolina Panthers as scheduled on Sunday, "after discussions between the league office, Head Coach Romeo Crennel and Chiefs team captains".
The Kansas City Chiefs have had a disappointing season so far, the BBC's Zoe Conway reports, with many fans calling for the sacking of the team's senior management.
A demonstration against the leadership due to be held on Sunday has been called off.
Outside Arrowhead stadium, Kansas City Mayor Sly James told reporters "there are a lot of people hurting,"
"There's a young baby right now without parents".