Phil Spector's lawyers told a court they could scientifically prove the actress he is accused of killing shot herself.
On Thursday, the second day of the music producer's murder trial, the jury heard Lana Clarkson accidentally committed suicide at the defendant's mansion in February 2003 while under the influence of alcohol and painkillers.
Defense lawyer Linda Kenney-Baden admitted they did not know Clarkson's motives but claimed she had been depressed.
Kenney-Baden said: "What we do know is that she put the barrel (of the gun) in her mouth. We know she was drinking, we know she was taking pills."
Spector's lawyers claim forensic evidence will prove he was not holding the shotgun when it went off, adding he was too far away to shoot Clarkson, 40.
Kenney-Baden explained that while "a lot" of gunshot residue (GSR) was found on Clarkson's hands and jacket none was found on Spector's shirt or the right sleeve of his jacket.
She said: "It proves that this means he did not shoot that gun. He was too far away to be holding the gun and get GSR on his clothes. It's not supposition, it's not hypothesis, it is scientific fact."
Lead defense attorney Bruce Cutler added Spector - who arrived at the Los Angeles court wearing platform shoes and a dark three-piece suit - "had no motive to hurt this woman and "harbored no malice towards this woman."
Meanwhile, prosecutors - who claim Spector, 67, had a "rich history of violence" and had previously pulled guns on unarmed women - called the producer's former girlfriend as their first witness.
Dorothy Melvin described a vodka-fuelled incident in 1993 during which her ex-lover confronted her with both a revolver and a shotgun, struck her twice in the head and ordered her to strip at gunpoint.
She said: "I was sobbing and I said, 'Why are you doing this Phillip? Why are you doing this?' I was crying. I was terrified."
When cross-examined, Melvin conceded she never pressed charges and maintained contact with Spector after the episode.
The musical genius will face life in prison if he is convicted of killing Clarkson at his Los Angeles hilltop mansion on February 3, 2003.
The trial, which is being televised live, is expected to last for up to three months.