(CNN) -- Former NFL quarterback Steve McNair was killed in a shooting in Nashville, Tennessee, authorities said Saturday.
Steve McNair, 36, spent 13 seasons in the NFL, the majority with the Tennessee Titans.
Police said they found McNair and a woman shot to death in a Nashville residence after receiving a phone call about an injured person.
The woman has been tentatively identified, but her name is not being released, authorities said.
A law enforcement source close to the investigation said the woman is McNair's girlfriend and that the residence is her condominium.
Witnesses said McNair was a frequent visitor there.
Authorities were questioning people who were near the home, but they said no one was in custody. Watch report on McNair's death »
They could not provide details about the circumstances of the shooting.
McNair's brother, Fred, also confirmed the death but had no immediate details.
McNair, 36, spent 13 seasons in the NFL, the majority with the Tennessee Titans, and was named the NFL's co-MVP in 2003. He spent his last two seasons with Baltimore Ravens before announcing his retirement in 2008.
The owner of the Titans, Bud Adams, Jr., said in a statement that the organization was "saddened and shocked" to hear of McNair's death.
"He was one of the finest players to play for our organization and one of the most beloved players by our fans," Adams said.
"He played with unquestioned heart and leadership and led us to places that we had never reached, including our only Super Bowl."
The Titans marked a Super Bowl loss to the St. Louis Rams in 2000.
McNair attended Alcorn State in Mississippi.
Dozens of fans who rushed to the crime scene were rattled by the news of McNair's death.
"I'm in shock. It's so hard to believe," Sonya Hughes told CNN affiliate WKRN. "Tennessee Titans, Steve McNair -- on the Fourth of July."
Ludy Wallace, former Nashville city councilman, remembered McNair as a "friendly" guy.
"I think he made an everlasting impression with people he came in contact with and the people that attended his [football] camps," Wallace told CNN affiliate WTVF.
