In the first of a two-part report on "The Early Show" Monday, CBS News Chief Investigative Correspondent Armen Keteyian had spotlighted some possibly faulty police conclusions.
The new revelations from police consisted of a 14-page case summary of their handling of the case. It provided some fresh details, including text messages between McNair and his 20-year-old girlfriend hours before the sexy young waitress allegedly shot him.
One message reflects a request for $2,000 from McNair to help pay her bills; others suggest she was stressed out and could hardly breathe, over money issues. Hours later, McNair transferred the money into her account.
But, Keteyian says in his second report, which aired on "The Early Show" Tuesday, CBS News has uncovered records of cell and text messages the Nashville police haven't made public.
Authorities have maintained from the start that Sahel "Jenni" Kazemi shot McNair, a 36-year-old married father of four who was almost a year-and-a-half into retirement, four times with a 9 mm pistol in the early morning hours of July 4 at a Nashville condo he rented with a friend before, police say, turning the gun on herself.
Police say she purchased the murder weapon from 33-year-old Adrian Gilliam Jr., a convicted felon who spent nine years in prison for second degree murder and attempted armed robbery. Gilliam told police he sold Kazemi the gun for $100, in a parking lot, two days before the deaths.
On July 8, Nashville Police Chief Ronal Serpas told reporters, "They transacted the deal ... and that, pretty much, is where that ends."
But gun powder residue tests on Kazemi's hands were inconclusive, and CBS News has learned there is little or no evidence on the gun sale -- just Gilliam's word.
So, Keteyian tracked Gilliam down to a Tennessee jail, where he's being held on federal gun charges related to the case.
In an exclusive interview -- no cameras were allowed -- Gilliam told Keteyian he sold Kazemi the gun on Friday, July 3, not Thursday, as police first said he did. Gilliam insisted to Keteyian that he barely knew Kazemi and couldn't even remember her name or how they met, describing a fleeting sort of relationship the U.S. attorney in Nashville, Edward Yarbrough, and Serpas portrayed as fact during a July 17 news conference.
"A casual exchange between two people," is how Yarbrough put it.
"He hardly knows who he's dealing with and yet he's selling a gun," Serpas said. " ... How they came together is probably happenstance."
But Kazemi's cell phone records, obtained exclusively by CBS News, tell a dramatically different story.
The records show all incoming and outgoing calls and text messages from Kazemi's cell between June 15 and July 14.
Not knowing CBS News had the records, Gilliam's father gave CBS News the cell phone number he says belonged to his son -- a "pay-as-you-go-phone" that's now disconnected.
CBS News ran that cell number against Kazemi's records, and it revealed that, in the three weeks prior to the deaths, Kazemi and Gilliam apparently communicated almost every single day, at all hours -- more than 200 calls and text messages back-and-forth.
The records show that, on July 3, the last full day of McNair and Kazemi's lives, she and Gilliam exchanged 49 texts and calls, far more than any other day.
"These communications are obviously more than someone in a casual relationship," Dennis Farrell, a former commander of a New York homicide squad, remarked to CBS News.
Asked by Keteyian whether, "When it turns out that he has lied about this," it ratchets up his suspicion about "whether (Gilliam) even put the gun in her hands or not," Farrell replied, "Yes. There's many, many questions."
Private investigator Wayne Black, a former detective, says he finds it disturbing that Nashville police took Gilliam's word for anything. "He's not only convicted felon, "Black observed, "he's a big liar. ... So, why did he lie?"
The cell records also show Gilliam was one of the last people to speak with Kazemi. He called her at 12:02 a.m. on July 4. They spoke for three minutes -- just two hours before, police believe, the deaths occurred.
That, says Black, is "a big deal."
Adding to the intrigue: Records show four texts from the same number to Kazemi after her death, including one the day after police had interviewed Gilliam.
"What should be done?" Black repeated a Keteyian question. "It's simple: The police should investigate further."
After months of "no comment," late Monday afternoon, in response to questions from CBS News, Nashville police said investigators have long known Gilliam's relationship with Kazemi was "more involved than initially believed."
A spokesman admitted the department was aware of the volume of calls and texts outlined in Keteyian's report, saying it was part what he called "the continuing investigation" since Gilliam's arrest. But, he said, nothing to this point in any way alters the murder-suicide conclusion.
All it does, it seems, is "open up an entirely whole new set of questions about the case," Keteyian concludes. The "big question," he adds, one he'd "like to see a lot more answers about," is whether "it was really (Kazemi)" who killed McNair and herself.