Eric Landry, 39, who had been staying in Brentwood, was charged Tuesday with murder, kidnapping, assault with a deadly weapon and residential burglary in connection with the Sunday morning attack, Cope said.
Landry is also facing an enhancement for the use of a firearm and a special-circumstance allegation of lying in wait, which makes him eligible for the death penalty, Cope said.
He is scheduled to be arraigned at 1:30 p.m. Wednesday in Contra Costa County Superior Court in Martinez.
The attack began at about 7:45 a.m. at Landry's estranged wife's home on Carol Lee Lane, police said.
The victim, 41-year-old Oakley resident John Provincio, had been staying at the house. When he stepped outside, Landry, who had allegedly been waiting for him, shot him, according to police.
Police said afterward that Provincio appeared to have been shot twice, including once in the head.
Landry's estranged wife called 911.
Police were not releasing details about what happened next, but said that when officers arrived, they found Landry inside the house with a gun, where he had allegedly kidnapped his estranged wife.
Officers called for a SWAT team, but Landry surrendered before the team arrived, police said.
Landry's estranged wife was not hurt, police said, and Provincio was airlifted to John Muir Medical Center in Walnut Creek, where he died.
Oakley police Chief Bani Kollo said he did not know the nature of the relationship between Landry's estranged wife and the victim.
Cope said he couldn't comment on a motive.
According to court records, Landry has no prior criminal record in Contra Costa County.
He is being held without bail in Contra Costa County jail.