Kansas City Chiefs player Jovan Belcher has committed suicide outside the team's training facility on Saturday morning after killing his girlfriend.
Kansas City police launched an investigation into deaths after Belcher, 25, shot dead his girlfriend at her home then drove to a practice facility near Arrowhead stadium and turned the gun on himself.
A spokesman said the player killed himself in front of Chiefs' head coach Romeo Crennel and general manager Scott Pioli.
"As officers pulled up and were getting ready to get out of their car, they heard a gunshot," police spokesman Darin Snapp said.
Snapp said police had minutes earlier been called to a nearby house after reports that a woman had been shot by her boyfriend.
The woman was later pronounced dead on arrival at hospital, local media reported.
The Chiefs released a brief statement. "We can confirm that there was an incident at Arrowhead earlier this morning," it said.
"We are co-operating with authorities in their investigation."
The Chiefs have won just one of 11 games this season, the worst record in the NFL. They were due to host the Carolina Panthers on Sunday.
Local media said it was still uncertain whether the game would be played but the Panthers had been instructed to fly to Kansas as planned.