That the gun found its way into the hands of McNair's 20-year-old mistress, Sahel Kazemi, is a tale of strange twists and turns and no small amount of misfortune. At any one of those turns, had something happened differently, McNair might still be alive. No one can know.
Federal authorities haven't said when the gun was born, but they know who made it - a now defunct California firm called Bryco, and later renamed Jennings, after a lawsuit involving an accidentally-killed 12-year-old boy, bankrupted the original firm.
Listen to the Chilling 911 Call.
Slide Show: McNair's Mistress and Hidden Life.
The gun was a 9mm and by 2002 it had made its way into a Tenn. pawn shop, where it likely sat under locked glass, flickering fluorescent bulbs shining off its metal skin.
Back in 1993, the gun's future owner, Adrian J. Gilliam., 33, of La Vergne, Tenn., was also living under flickering fluorescent lights. He was in a Florida jail for three counts of second-degree murder and attempted robbery.
He got out in 2002, serving only nine years of a 17-year sentence, according to the Tennessean, who said his release was due to good behavior and good fortune. He was convicted two years before a 1995 Florida law was enacted which requires convicts to serve 85 percent of their sentence.
By his family's accounts, when Gilliam was released he worked to turn his life around. His father said he was "keeping straight" and taking care of his family.
He found a job in the car business, fathered a child, and settled down with the baby's mother with whom he is currently engaged.
Sometime in 2008, their home was broken into and Gilliam grew fearful for his new family. Even though he was a convicted felon, he bought the 9mm Bryco/Jennings pistol for his wife's protection.
But his wife was weary of having a loaded weapon around their two-year-old child. She told Gilliam to get rid of it, according to Nashville Police Chief Ronal Serpas. Gilliam had also lost his job and now was hoping to trade cars privately to make ends meet.
That's how he met the woman who, two nights later, would murder Steve McNair and take her own life. Sahel Kazemi, a slim figured and by most accounts personable waitress at Dave & Busters wanted to sell her Kia. She met Gilliam in the parking lot of the Dave & Busters where she worked, the very same restaurant in which she originally met Steve McNair.
Gilliam didn't buy her car, but he did sell her that gun, fully loaded, for $100. Later that night, Kazemi was pulled over by police for drunken driving. She claimed she was not drunk, but high. A police video shows her walking a line in a tight mini skirt, her white platform heels left by the side of the black Escalade she was driving. In the video, McNair can be seen slinking away from the giant SUV. He would later bail her out of jail.
By now the stage was set.
No one knows exactly what happened in that final 48-hour countdown between Gilliam meeting Kazemi to buy a car and instead selling her a murder weapon.
Police have speculated that Kazemi believed McNair had another young mistress and she was also distressed over money problems. According to her family, Kazemi believed McNair was going to leave his wife and move in with her. Perhaps the night of the murder she found out otherwise.
Whatever it was, it's unlikely that on July 4, McNair understood how distraught Kazemi had become. He was asleep in his Nashville condo when Kazemi pulled out the 9mm and unloaded two bullets into his chest and two into his brain, one from only inches away. Then, according to police, she positioned her body so it would fall into McNair's lap when she died. Kazemi drew the pistol and fired a final bullet into her own skull.
When police arrived her body had already fallen to the floor. The gun lay beneath her crumpled body in a pool of the killer's own blood.
Gilliiam was charged Friday with being a convicted felon in possession of a firearm. He faces up to 10 years in prison and a $250,000 fine.
PREVIOUSLY ON CRIMESIDER
July 17, 2009 - Convicted Killer Provided Gun that Murdered McNair
July 13, 2009 - McNair and his Mistress: A Deadly Play by Play
July 10, 2009 - McNair Memorial: Thousands Attend Service For Ex-NFL Star
July 9, 2009 - McNair 911 Call: "Oh My God...Somebody's Been Shot."
July 9, 2009 - Caught on Tape: McNair's Mistress DUI Video
July 8, 2009 - McNair Murder: The Mistress Did It
July 8, 2009 - Love Pad to Death Pad: Gruesome Details of NFL Star's Murder Scene
July 7, 2009 - McNair Murder: The Girlfriend's Gun
July 6, 2009 - The Girl, The Gun and The Dead NFL Star