Jurors convicted two Sonoma County men of second-degree murder Tuesday in a Healdsburg-area pot garden slaying that stoked fear about violence at marijuana farms.

Sidonio Cruz-Santos, 36, of Santa Rosa and Agustin Zepeda-Onofre, 25, of Windsor, were convicted of killing Gabino Lopez-Santiago, 46, of Healdsburg.

The two men, who witnesses said were frequently armed, were growing marijuana on a wooded hillside on Chemise Road near Dry Creek Valley. Lopez-Santiago was the brother-in-law of a man they hired to trim and process their pot.

The night of the killing, they were all partying at the garden when an argument broke out and Lopez-Santiago and his brother-in-law were ordered to leave at gunpoint. Lopez-Santiago was shot by one of the defendants as he waited for his brother-in-law to get their truck.

It was unclear who pulled the trigger but both defendants were convicted under a "vicarious liability" theory, which held each man legally responsible for the actions of the other. Jurors rejected first-degree murder, which required a finding of premeditation.

"It was a just decision," prosecutor Anne Masterson said. "I feel confident in the verdict."

It came after about five days of deliberation. The trial spanned three weeks.

Each man was also convicted of three counts of assault with a firearm and felony cultivation. Cruz-Santos was found guilty of persuading a witness by force or threat.

They face life prison terms when they are sentenced.

They are the latest to be convicted in a series of pot-related homicides to strike Sonoma County in the past few years. In December, two men were convicted of murder in an October 2011 pot rip-off outside a southwest Santa Rosa meat market. Three men await trial in a February triple-slaying near Forestville that police say is tied to a pot deal.

The Feb. 5 triple homicide happened as trial was starting in the Healdsburg case. Attorneys agreed to postpone the trial for one month because of publicity surrounding the issue of pot and violence.

Cruz-Santos and Zepeda-Onofre were growing about 30 plants on Chemise Road and more marijuana at an undisclosed spot. They had documents showing the garden — which police said could produce up to 90 pounds of marijuana — was destined for a disabled Santa Rosa woman with a medical recommendation.

The prosecution's key witness was the victim's brother-in-law, Ramon Lopez-Velasco, who was initially charged with murder but testified under a grant of immunity.

Lopez-Velasco said the defendants brandished weapons and fired into the air to scare off trespassers. He said both were holding guns when he returned from getting the truck to find his brother-in-law dead.

They forced him to dump the body on Mill Creek Road, he said.

Defense attorneys questioned his credibility, pointing to his changing stories about what happened. They blamed another man, Conrado Valentin-Cruz, as the only person with a motive to kill the victim. He remains at large.

Kristine Burk, Zepeda-Onofre's lawyer, said the verdict reveals that "the jury doesn't really know who did it."