On January 5, 2013, in Knoxville, Tennessee, Lee Byford stepped out of his home the night of his birthday, not knowing his killer was waiting for him.

A last-minute decision with deadly consequences, leaving some to wonder: Was it a random robbery or a targeted hit?

It was Lee Byford's 37th birthday. Little did he know it's also the day he will die.

Just hours before the tragedy, Lee's mother Ann Marotti, woke up excited to be the first to wish her son a happy birthday. Lee tells his mom he plans to have dinner with his girlfriend Tiffany.

"I'm going to kind of like decorate my living room and dining room and fix him something to eat so when he gets off, he can kinda celebrate his birthday a little bit," said Tiffany.

Lee had just put in a long day at his Knoxville, Tennessee auto-painting shop with his friend and coworker Jackie Sutton.

"All day long. You know, I had work from, I want to say it was 9:30 till 6, 6:30, somewhere around there. And he was going home to eat," said Jackie Sutton.

But when Lee arrives home after work, he's unusually late, and not alone.

"He came in the house, I was like 'You're late,' you know, 'I had something planned for you,' and he was like 'I know, I understand,' he said, 'But I have to take Gerod home,'" said Tiffany.

Gerod Murphy was a new buddy of Lee's.

"Gerod and Lee were introduced from Lee's friend. Gerod was out of work at the time and needed to make some money and asked him 'Do you have anything you need done at your business where he could work for you a little bit?'" said Dean Huff, Lee's best friend. "He was trying to help him out."

And on that night, that included a ride home.

"And I said 'OK, so when will you be back?' And he said 'I'll be back a little later, I promise,'" said Tiffany. "I said 'OK.'"

But it's a promise Lee won't keep. Within seconds of stepping outside of his house:

"I heard like something ricocheting off of his truck, so I was like 'What the heck was that?'" said Tiffany.

Panicked, Tiffany flings open the curtains.

"'Oh my God, what is going on?'" said Tiffany. "I seen a guy like about 5'5" or something, with a blue hoodie on, like it was all covered up his face, like he had a black mask on or something, black gloves, he had a gun pointing directly at his SUV."

Screaming at the top of her lungs, Tiffany runs out on the front porch. The masked gunman doesn't flinch, and runs to the driver's side window of Lee's SUV. Now he is mere inches from Lee, who has managed to lock the door.

"But he was beating on the side of his window, and I was on the porch, screaming 'Please leave him alone, go away,'" said Tiffany.

But the masked gunman won't back off.

"At that point the gunman is trying to open the door," said Knoxville Police Investigator Brandon Wardlaw.

Wardlaw says at that moment Lee was in big trouble.

"Byford puts the truck in reverse, drives to back down the hill, I would say to get away," Wardlaw tells Crime Watch Daily.

As Lee Byford races away in reverse, Gerod Murphy sits in the passenger's seat.

"The next thing you know there's a gunshot. At that point, he says, Byford looks at him and says 'I think I'm hit,'" said Wardlaw.

Tragically, Lee Byford has been gravely wounded in the left side of his chest. Investigators say at that point Murphy stepped on the accelerator. After Lee is shot, the truck rolls down the driveway and gets stuck in a ditch where the driveway meets the street.

Cops are on the scene quickly. Investigators secure the area, but the masked gunman is nowhere to be found. Lee Byford is still behind the wheel of his SUV, and he's not moving.

"Byford was pronounced dead on the scene," said Wardlaw.

And the passenger in the car, Gerod Murphy? He was unscathed.

Police interviewed Murphy. He told investigators he was sitting in the passenger's seat waiting for Lee to come out of his house.

"Next thing he knows, the gunman comes from around the fence. Byford tries to get back to the vehicle and he's able to get in the driver's side and close the door," said Wardlaw.

Murphy says that's when the masked man fired his gun point-blank at Byford.

Why do you think Lee Byford was shot and not Gerod Murphy?

"That's something that still puzzles me to today. This whole thing is kind of mind-boggling," said Brandon Wardlaw.

Investigators process the crime scene. It appears to be a straightforward robbery -- minus one thing: the robbery.

"Nothing was taken. I think that once Byford got in the truck, he messed the whole thing up," said Wardlaw. "If they could have got to him before he got in the vehicle and got whatever they thought he had on him, I think they would have just took it and ran."

Investigators scour the crime scene looking for anything that will point them in the direction of a potential suspect.

"We were able to locate a piece of chewing gum, I think an earring that we confiscated. We actually went back the next day with a metal detector to make sure we didn't miss any shell casings," said Wardlaw.

The one thing cops do have is a partial description of the gunman.

"A blue hoodie or sweatshirt, and a black ski mask," said Wardlaw.

Then just days after the shooting, Knoxville Police get what seems to be a huge break in the case when they receive a call from Tiffany Cannon.

"I'm at the house, I look down and I see a black mask on the ground," Tiffany tells Crime Watch Daily.

"There's no way I missed that ski mask," said Wardlaw.

Lee Byford had been at work at his auto body shop all day when he made a quick stop at his home. When he walked back outside, he walked into a trap.

Lee Byford's friends and family claim they have plenty of reasons to believe that Lee's new buddy Gerod Murphy set him up.

Lee's girlfriend Tiffany claims Lee told her that Gerod was working with him on the day of the incident, and according to Tiffany, that meant Gerod had firsthand knowledge of one key thing:

"Lee told me he was going to get $500 that day," said Tiffany.

And the payment would be in cold hard cash. That's something Knoxville Police say could have made Lee Byford a marked man.

Lee's best friend Dean Huff has some serious questions about the robbery-gone-wrong theory.

"If it was random, how did they know when he was coming home?" said Huff.

Then there's the fact of where Lee lived. It's not easy to find.

"You wouldn't stumble across it," said Dean. "So how would anybody that didn't know Lee know here he lived, or even if they did, there's only so many people that had even been there."

And Lee's mother points to something odd that Gerod Murphy did right after the murder. According to police, when they arrived on scene they discovered Murphy walking up from the bullet-riddled SUV toward Lee's house.

"The fact that he was walking back, that's what has always bothered me," said Lee's mother Ann Marotti.

Because the shooter is still out there?

"Yes," said Marotti.

Lee Byford arrived home late on the night he was killed. Now cops can confirm where he was just minutes before his murder.

"We have video surveillance of Byford and Gerod Murphy going to the Stop N Go market before they ended up going to Byford's residence, where the incident took place," said Knoxville Police Investigator Brandon Wardlaw.

So about five minutes before he was shot, he was at the convenience store.

"Yes ma'am," said Wardlaw.

The surveillance video has not been made public, but reportedly it shows Lee going inside the store to buy a drink, and then Gerod is seen walking out of frame to talk to someone. That makes Lee's family very suspicious. But investigator Wardlaw says Murphy has been cooperative, and his story about the night in question appears to be credible.

"He came in and spoke with me on three different occasions," said Wardlaw. "But he's in a very odd situation from sitting in the car with Byford when the incident took place and going from being a witness to being accused by several people that he might have something to do with or he set this whole situation up."

Is Gerod Murphy a person of interest?

"Right now, he's not, he is a witness for me. I have nothing pointing to him showing that he could of any way set this up or done it," said Wardlaw.

Gerod Murphy has not been arrested or charged in any connection with Lee Byford's death. Lee's family and friends are desperate for answers.

"I would love it if you guys could make contact with Gerod and have him retell the accounts of that night, what really happened," Dean Huff tells Crime Watch Daily.

We started looking for Murphy and found him online in homemade rap music videos he posted to Youtube.

From last-known addresses listed for Murphy, we zero-in on a particular home. Murphy was reported living there with his brother, and the house appears to match the background that was featured in some of his music videos. As we set up our cameras, it appears someone is home. The man identifies himself as Gerod's uncle.

"He does not live here, neither one of 'em. Now, you put that on the air. He do not live here. This is my house. They don't live here. They got their own houses. I don't care if they shoot videos wherever. Yes, they're my nephews. I don't know what they've done. Don't come back over here."

It's been five years since Lee Byford was murdered. His family has offered a $5,000 reward, and yet still no answers.

"No tips whatsoever. Not one call," said Brandon Wardlaw.

January 5, 2018 would have been Lee's 42nd birthday. Tragically, his mother now has to celebrate her son's life and death on the same day.

"I would say, as a mother, if it were your son, what would you do? You need to speak up. We need closure. We need justice," said Ann Marotti.

Anyone with information on Lee Byford's death is asked to contact the Knoxville Police Department at (865) 215-7212. The $5,000 reward is still available.