What happened to Steve McNair? The true story behind the Netflix 'Untold' episode

The inspiring rise and tragic death of former Tennessee Titans star quarterback Steve "Air" McNair are back in the spotlight.

A new episode of the Netflix sports documentary series "Untold" follows McNair's path from a small college to NFL stardom, while also examining questions about the police investigation into McNair's death in 2009.

The one-hour episode titled "The Murder of Air McNair," which started streaming on Aug. 20, jumps between timelines of his ascendance to a Super Bowl quarterback and the aftermath of his death.

Here's what to know about the star's life and tragic death.

Who was Steve McNair?

The Mississippi native rose to national prominence in the early 1990s during his football career at Alcorn State, a historically black university in his home state.

McNair won the Walter Payton Award as the top player in what was then called Division I-AA (now the Football Championship Subdivision) during his senior season by racking up a combined 6,281 yards and 56 touchdowns.

He became the rare small-school player to finish in the top five in Heisman Trophy voting for college football's most prestigious award, taking third following his brilliant senior season. No FCS player has been a Heisman finalist since McNair in 1994.

McNair then achieved another rarity for a small-school player by being selected No. 3 overall in the 1995 NFL Draft by what was then the Houston Oilers. (The team is now the Tennessee Titans.)

A physical runner with a strong arm, he was the team's star quarterback when they made the move from Houston to Nashville and became the Titans.

In their first season in Tennessee in 1999, the Titans went undefeated in their new home stadium to reach the playoffs under head coach Jeff Fisher, who is interviewed in "Untold."

They beat the Buffalo Bills in the first round of the postseason on a wild kickoff return touchdown in the final seconds that became known as the "Music City Miracle" in NFL lore.

They rode that momentum all the way to the Super Bowl, where they lost 23-16 to the St. Louis Rams. McNair hit Kevin Dyson with a pass in the final seconds, but Dyson was tackled one yard short of the goal line with no time left.

McNair led the Titans to two more AFC title games before ending his career with two seasons on the Baltimore Ravens in 2006-07. He played 13 seasons, which included being named the NFL's co-MVP for the 2003 season and reaching three Pro Bowls. His No. 9 jersey has been retired by the Titans.

How did Steve McNair die?

McNair was found dead by police on July 4, 2009, at a condominium rented in his name in Nashville. His body had four bullet wounds and was found next to the body of Sahel "Jenni" Kazemi, 20, who had one bullet wound to the head, police said.

The episode of "Untold" begins with the 911 call to police. McNair's friend, former Alcorn State teammate and business associate Robert Gaddy, made the call.

The Nashville Police Department ruled after an investigation that it was a murder-suicide. Kazemi shot McNair to death before shooting herself in the head, police said. A gun was found under Kazemi and gunpowder residue was found on her hand.

What was Steve McNair's relationship with Sahel Kazemi?

Kazemi was a waitress at a local Dave & Buster's restaurant in Nashville with whom police said McNair was having an affair.

McNair had been married to his wife, Mechelle, for 12 years and had three children at the time of his death. McNair's wife and children are not interviewed in the episode.

Excerpts of police interviews with Kazemi's coworkers, family and friends featured in "Untold" include them saying that McNair and Kazemi had talked about adopting children and building a life together. He was publicly seen with her and told her he was going to get divorced, according to their testimony.

Kazemi's roommate, Emily Andrews, told NBC Nightly News anchor Lester Holt in 2009 that she went to clubs with Kazemi and McNair and "people saw that they were dating."

Police also released text messages between Kazemi and McNair. In one of them, she asked for help financially. In another, she wrote she "might have a breakdown" because she was "so stressed."

Nashville authorities checked McNair's phone records and discovered he was involved with multiple women, one of whom was interviewed by detectives, according to the documentary. People close to Kazemi interviewed by police said she had realized McNair was seeing other women.

Police concluded Kazemi purchased a gun only hours after getting cited for driving under the influence, two days before McNair's murder. They said she bought it off a Tennessee man named Adrian Gilliam, a convicted felon who was on parole after serving time for second degree murder and attempted robbery.

What is the dispute over the police investigation into McNair's murder?

A private investigator named Vincent Hill, who has written a book about the investigation, questions its findings in an appearance on "Untold."

“I think once people start to see the gaps, the holes and the things that don’t make sense in this case, anybody with common sense is going to say, ‘Wait a minute guys, like, you screwed up,’” Hill says in the episode.

Hill points out that Gilliam initially told police he didn't know Kazemi's name when he sold her the gun, but police later found more than 200 calls and text messages between them in the three weeks before McNair's murder.

He also claims Gilliam lied about his whereabouts at the time of the shooting and that he was the last one in contact with Kazemi on the day she and McNair died.

Hill then alleges it may have had something to do with Gaddy. Nashville detective Charles Robinson says in the episode that Gaddy had a falling out with McNair over $13,000.

Gaddy vehemently denies Hill's assertion in the documentary.

"You think I'm involved with my best friend's murder over 13 freakin' thousand dollars?" he said. "I've had to listen ridicule and conspiracy theories, but deep down I'm feeling this weight that only if I had not had an argument (with McNair), I would've been there for him."

Robinson also refutes Hill's claims.

"Ask him for his resume," he says about Hill. "Ask him, how many murders did you work on the police department? Zero."

"What Vincent Hill did and is doing is totally disgusting," Gaddy said.

McNair's former head coach, Jeff Fisher, also weighs in on the allegations.

"I could make a case that things don't add up," Fisher says. "I don't want to speculate. Just let it go."

This article was originally published on TODAY.com