Jurors at a murder trial highlighting Nevada's stand your ground law must decide whether an elderly Sparks man is a premeditated killer or justifiably acted in self-defense when he fatally shot one unarmed trespasser and seriously wounded another, lawyers on both sides said Tuesday.

Wayne Burgarello, 74, admits he killed Cody Devine and shot Janai Wilson when he confronted them last year in a rundown, abandoned duplex he owns.

But prosecutors and a defense lawyer offered widely contrasting theories as to his motivation during their opening statements in the Washoe District Court trial, which is expected to last two weeks.

"The state will fail to prove that this is a cold, calculated, premeditated, lying-in-wait murder, simply because — ladies and gentlemen — it's not," Burgarello's lawyer, Theresa Ristenpart, told the jury.

Burgarello thought Devine was pointing a gun at him in the darkened back bedroom, she said. Although no weapon was found at the crime scene, the retired school teacher may have mistaken a black flashlight that police found beneath Devine's body for a gun, she said.

"Under our laws, Wayne acted in justified self-defense," Ristenpart said. "In a split-second decision ... he shot because he believes his life was threatened in a bedroom where no one should have been."

The case is the latest among several similar in the dozens of states across the nation with stand your ground laws that allow property owners to use deadly force when they fear their life is in danger. Like some others, Nevada's law carries a caveat that the killer must not have been the original aggressor.

Assistant District Attorney Bruce Hahn argued that Burgarello was in fact the initial aggressor.

Armed with a 9-mm pistol in one hand and a .357-caliber handgun in the other, Hahn said Burgarello broke through the chain-locked door of the duplex that had been abandoned for 9 years before advancing to the back bedroom, where Devine and Wilson had been injecting methamphetamine in the early hours of Feb. 13, 2014.

"Calling out, he opens the door and sees two forms on the floor under a blanket, a white comforter, and opens fire," Hahn said.

Devine, 34, was shot five times, killed by a bullet that passed through his skull. Wilson, 29, was shot three times, but she survived and is expected to testify at the trial. Hahn said she believes Burgarello didn't stop shooting "until he ran out of bullets."

Hahn said Burgarello called police about once a year the previous 15 years with various complaints ranging from burglaries and vandalism to barking dogs. But he didn't call 911 the day of the killing, instead deciding to take the law into his own hands, Hahn said.

Neighbors and police officers will testify that Burgarello had told them repeatedly during the previous four years — including a week before the killing — that he was considering arming himself and waiting inside to catch those responsible for past burglaries, Hahn said.

Judge Patrick Flanagan said Burgarello is entitled to claim self-defense as long as he truly believed there was imminent danger he'd be killed or suffer great bodily harm, and that another person placed in a similar situation would reasonably conclude it was absolutely necessary to use deadly force.

As long as Burgarello "made a good-faith effort to decline a struggle before the fatal blow is delivered ... he has a right to stand his ground and need not retreat," Flanagan said. That holds true even if it turns out later the shooter "was mistaken about the presence of danger," he said.