NASHVILLE - Shot twice in the head and two more times in the chest, former NFL quarterback Steve McNair was the victim of a homicide, police declared yesterday. But authorities would not say it was a murder-suicide, even with his 20-year-old girlfriend dead at his feet from a single bullet.

McNair, 36, had been dating Sahel Kazemi for several months, and a semiautomatic pistol was found under her Saturday, Nashville police spokesman Don Aaron said yesterday. She had been shot in the head.

McNair, who was married with four sons, had a permit to carry a handgun in Tennessee, and was arrested once with a 9mm weapon, although charges were dropped. Police said they had not determined who owned the gun found at the scene.

Investigators were not looking for a suspect but were questioning friends of the couple and a former boyfriend of Kazemi's. They also were waiting for results of drug and other laboratory tests before deciding whether McNair was killed in a lovers' quarrel.

"That's a very important part of the investigation as we work to ultimately classify Miss Kazemi's death," Aaron said.

The details surfacing after McNair's death stand in stark contrast to the public persona he enjoyed during his career.

McNair repeatedly played through serious injuries and pain to win, although one of his pass completions came up a yard short of forcing overtime in the Tennessee Titans' famous drive in the 2000 Super Bowl.

He frequently took part in charity work for the Titans and later the Baltimore Ravens after a 2006 trade. McNair helped load donated food, water, and clothes onto tractor-trailers that he had arranged for Hurricane Katrina victims, and paid for three football camps for children this year.

McNair and Kazemi were found at a Nashville condominium that overlooks the Titans' stadium and that he rented with his friend Wayne Neeley. Police said they believed the couple died early Saturday. Neeley found the bodies hours later and called a friend, Robert Gaddy, who played with McNair at Alcorn State in Mississippi. Gaddy dialed 911.

The quarterback's agent, Bus Cook, said he had never heard Kazemi's name until news of the shooting broke Saturday. What McNair's wife of 12 years, Mechelle, knew was not clear yesterday. Cook said she had no comment after the police called her husband's death a homicide.

Mechelle McNair was "very upset, very distraught" yesterday, Cook said. She was preparing to finish funeral arrangements today.

McNair split his time between Nashville and his farm in Mount Olive, Miss. Last month, he opened a restaurant near Tennessee State University.

McNair was seen so often at Kazemi's apartment that a neighbor thought he lived there.

McNair met Kazemi when his family ate often at the Dave & Buster's restaurant where she was a server, and the two began dating.

A man who answered the door at a house in the Jacksonville, Fla., suburb of Orange Park said it was the home of Kazemi's family but said her relatives did not want to comment.

"We don't have anything to say. Please leave us alone," he said.

The woman's sister, Soheyla Kazemi, told the Florida Times-Union that Kazemi had expected McNair to get a divorce. "She said they were planning to get married."

Nashville courts had no record of a McNair divorce case, but a home he owned in Nashville is on the market for $3 million.

The real estate agent declined to comment. Her online listing for the property described it as a "gigantic house" of more than 14,000 square feet, and photos showed a pool, a home theater, a baby grand piano, and ornate furnishings.

A limousine often dropped off Kazemi at home in the early morning, and she recently went from driving a Kia to a 2007 Cadillac Escalade registered to herself and McNair.

The two were together Thursday night when Kazemi was pulled over in the Escalade. She was arrested on a DUI charge; McNair was allowed to leave in a taxi.

McNair led the Titans to the 2000 Super Bowl, which they lost, 23-16, to the St. Louis Rams despite his 87-yard drive in the closing minute. He was co-MVP of the NFL with Colts quarterback Peyton Manning in 2003.

Manning said in a statement that the two quarterbacks had some great battles.

"Sharing the NFL MVP honor with him in 2003 was special because of what a great football player he was," Manning said. "I had the opportunity to play in a couple of Pro Bowls with him, and the time spent with him in Hawaii I'll never forget. I'll truly miss him."

The Titans drafted Vince Young in 2006 to replace McNair, who had mentored Young since he was a teenager. They never played together but did play against each other that year.

"He was like a father to me," Young said in a statement yesterday. "I hear his advice in my head with everything I do. Life will be very different without him."

McNair grew up in Mount Olive and became a football star at Alcorn State, a Division I-AA school, as he dominated the Southwestern Athletic Conference. Nicknamed "Air McNair," he became a Heisman Trophy contender, finishing third in the voting in 1994.

He still holds Division I-AA (now the Football Championship Subdivision) records for career yards passing (14,496) and total offense (16,823). McNair was drafted third overall in 1995 by the Houston Oilers, who eventually became the Titans.

Picked four times for the Pro Bowl, McNair finished with 31,304 yards passing and 174 touchdowns. He led the Titans and Ravens to playoff berths, including two AFC championship game appearances with Tennessee. Injuries led to his retirement after the 2007 season.

Besides his wife, McNair is survived by his sons, Junior, Steven, Tyler and Trenton.