The state of Tennessee says Ronald Cosper shot Steve Mosley to death in his Avondale home during a robbery in 2012.
But Cosper's attorney says that's impossible.
"He's not guilty, because he was not there," attorney Andrew Basler told a jury Tuesday.
Cosper, 21, is one of three men charged in Mosley's death, and the first to go to trial on charges of felony murder, criminal trespassing, aggravated criminal trespassing, attempted especially aggravated robbery and conspiracy to commit aggravated robbery.
Also charged are Devante Stoudemire, 22, and Dustin Hayes, 21. Hayes pleaded guilty to facilitation to commit aggravated robbery last week. Charges of first-degree murder and aggravated robbery against him were dismissed. Stoudemire's case is pending.
During opening statements Tuesday, Assistant District Attorney General Cameron Williams described a robbery he said Cosper had been planning for months. Mosley, 39, lived alone in a duplex, did not work and liked to play video games. He sold marijuana on the side, Williams said.
Cosper called Mosley "the weed man," and saw him as weak, Williams said. He called on Hayes for a ride and asked Stoudemire to find him a gun, and went to Mosley's Hawthorne Street home to rob him. When Mosley put up a fight, Williams said, Cosper shot him three times.
After, Cosper reportedly said "I had to burn somebody," Williams said.
Basler, Cosper's attorney, said prosecutors have no evidence to prove a robbery even happened, let alone that Cosper was its perpetrator. He cautioned jurors to listen closely to Hayes' testimony -- he just told police what they wanted to hear, Basler said.
On Tuesday, a neighbor who lived next door to Mosley described seeing a "scuffle" between Mosley and another man, then running inside to shield the children there after she saw a gun.
Marquita Swanson said she heard three shots, then Mosley stumbled into her side of the duplex, bleeding. He cried and asked her to call his brother. Then he was dead.
"I was trying to talk to him as he was taking his last breaths," Swanson said.
Swanson began crying and another woman left the room sobbing after Williams projected photos of Mosley's crumpled body on a screen.
The trial is expected to resume Wednesday afternoon.
Contact staff writer Claire Wiseman at email@example.com. Follow her on Twitter @clairelwiseman.