A sharpshooter shot and killed Flores following a five hour stand off at his family's home on Audrey Lane. Investigators say Flores was holding an assault rifle in a threatening manner as he walked out the back door to get away from tear gas that had been launched into the home. He was declared dead on the scene.
The suspect fired shots out of the home on more than one occasion causing gathering neighbors to run for their lives and members of the media to hit the ground.
Police said before Flores walked out the back door, Flores first responded to the tear gas by firing more shots out the front door.
The stand off started around 11 a.m. and did not end until around 4 p.m. It all started with a report of two men arguing around 10:50 a.m. When police arrived, one of the men fired off a shot before running into his house.
Negotiators were called and attempted to make contact with the suspect using a bullhorn.
Flores' father told reporters he begged negotiators to allow him to talk to his son, but they said that was not allowed.
The Sunvalley Mall was not evacuated and remained open. Some shoppers had trouble getting to their cars because of a police staging area. Security officers at the mall were sent to retrieve cars one at a time.
People who lived near the home were told to shelter in place and were asked to use keep their cell phone use to a minimum.
During the standoff, a male victim with two minor gunshot wounds checked himself into an area hospital. He is believed to be a known associate of the man involved in the standoff, police said.
Contra Costa County sheriff's spokesman Jimmy Lee identified the SWAT team member who killed Flores as Sgt. Robert Hartman.
Hartman, 44, has been with the sheriff's office for nearly 20 years. His current assignment is with the city of Oakley, Lee said. He has been placed on paid administrative leave while the shooting is investigated.
Investigators recovered an assault rifle, a semi-automatic handgun and empty shell casings from Flores' home.
Neighbor Ginger Charles, who lives on nearby Audrey Court, said she was driving home from church when she saw the streets near her home were blocked off.
"I couldn't see much, I could just hear the bullets being shot," she said.
She parked and walked to her house where she received automated calls from police.
"We were told to stay in our houses with doors locked and windows locked," Charles said.
"It was scary," she said. "I've never seen more police in my life."
She said she doesn't have Internet service at home, but that a neighbor kept her informed of each development as the online news sites updated the story.
Connelly pointed out that Sunday's outcome could have been worse.
"We were extremely lucky that no officers were injured, considering the number of rounds that were fired, and we were very lucky that no innocent civilians were injured," he said.
The Pleasant Hill Police Department, the Contra Costa County Sheriff's Office and the Contra Costa County District Attorney's Office are investigating the incident.