Defense attorney Joseph Bisbiglia told the jury Miller bought a gun for protection because his sister and Neuer were growing marijuana.
A Cloverdale man was sentenced Friday to 50 years to life in prison for killing his sister's boyfriend last year.
Jarrod Miller, 30, was convicted March 1 of first-degree murder, use of a firearm and residential burglary.
Miller shot 29-year-old Timothy Neuer three times March 8, 2011, at the Healdsburg home he once shared with him and his sister Amanda.
Sonoma County District Attorney Jill Ravitch, who tried the case with Deputy District Attorney Scott Jamar, told the jury in her closing argument that anger and resentment fueled Miller's plan to kill him.
Neuer considered Miller a "mooch" and too dependent on him and Amanda Miller, Ravitch said.
Miller later moved to a Cloverdale home his sister and Neuer owned, according to trial testimony. Ravitch told the jury Miller felt unwelcome, considered that the end of his lifeline to his sister and her support and began planning Neuer's murder.
Amanda Miller testified that her brother said, "It's going to be OK now Mandy, it's going to be alright," after he shot Neuer as the victim came out of the bathroom where he was getting his head shaved.
Defense attorney Joseph Bisbiglia told the jury Miller bought a gun for protection because his sister and Neuer were growing marijuana. He said Miller suffered from mental illness.
Bisbiglia said Neuer was aggressive when he emerged from the bathroom, "towered over" Miller and told him to "get the f--- out of the house." Miller feared for his life "and just snapped," Bisbiglia said.
The jury deliberated two days before convicting Miller.
At the sentencing Friday, members of Miller's and Neuer's families filled the courtroom where two videos with photographs of Neuer were shown and a letter by Amanda Miller was read, Ravitch said.
"In choosing to take a friend's life so violently, the defendant brought tragedy to two families. The sentence is appropriate for this heinous act," Ravitch said.