The victims of the mass shooting in Thousand Oaks, California, include army veterans, students and a police officer.
The families of the dead have paid tribute hardworking, loving and energetic characters.
Here is what we know about those who were killed.
Sergeant Ron Helus, 54
The married father-of-one died of gunshot wounds as he moved in to try to stop the killing spree.
He was hailed as a hero who had likely saved lives.
Fellow officers from the Ventura County Sheriff's Office described him as an "exceptional friend and man" who had served for 29 years as one of the most committed and hardworking officers on the force.
"The fact that he was the first in the door doesn't surprise me at all," said Sergeant Eric Buschow.
"He's just one of those guys that wouldn't hesitate in a situation."
"When you call 911, he's one of the guys you want showing up," he continued.
"If you were a victim of a crime, you want him investigating the case. He would go to the ends of the earth to find a suspect. Just an awesome investigator."
Cody Coffman, 22
Mr Coffman was confirmed to have died during the attack by his father, Jason.
He told reporters that his son – who had two younger brothers, aged eight and six – had been planning to join the military and was also looking forward to the arrival of a baby sister later this month.
Speaking through tears, Mr Coffman said: "I talked to him last night, before he headed out the door.
"First thing I said was, 'please don't drink and drive'. Last thing I said was, 'son, I love you'. That was the last thing I said."
Justin Meek, 23
Justin Meek had recently graduated from university and was working as a caregiver, supporting families with special needs.
He also toured professionally as an acapella singer.
California Lutheran University President Chris Kimball confirmed in a statement that Mr Meek was among the dead, adding that he had "heroically saved lives in the incident".
He said: "We will pray, begin to comfort one another in our grief, and hold the families, friends and loved ones of the victims in our hearts.
"California Lutheran wraps its arms around the Meek family and other families, and around every member of this community of caring."
Alaina Housley, 18
Alaina Housley, a student at Pepperdine university who was described as loved by all who knew her, also died.
She was the niece of actress Tamera Mowry-Housley and husband Adam Housley, who issued a plea to find her in the hours following the attack.
In a joint statement, the couple said: "Alaina was an incredible young woman with so much life ahead of her and we are devastated that her life was cut short in this manner.
"We thank everyone for your prayers and ask for privacy at this time."
Noel Sparks, 21
A regular at Borderline, spending Halloween and her 21st birthday at the club, Noel Sparks was described by her aunt Patricia as an "all-round good girl".
"She was the kind of girl that if you had friends, you'd want them to marry her," she said.
Reverend Shawn Thornton described her as artistic and a leader in church activities, who worked part time helping with children's programs at the local church and majored in art at nearby Moorpark College.
"She loved kids. We had a lot of parents show up today to say, 'She made my child feel important and that they mattered," Rev Thornton said.
Sean Adler, 48
A security guard at Borderline, Mr Adler was married with two children.
Longtime friend Debbie Allen said he had a "big personality" and would often stay late at the bar to ensure people would get home safely.
"I don't think in all the years I've known him, and it's almost 30, I ever heard him say no to someone," she said.
Mr Adler was also passionate about coffee and had recently opened his own coffee shop, Rivalry Roasters, with friend Phil Englander.
He described him as "energetic" and "just a warm and friendly and passionate person about everything in his life."
Telemachus Orfanos, 27
Mr Orfanus, 27, had survived last year's Las Vegas shooting, in which 59 people were killed at a country music festival, only to be killed at the Borderline bar.
It is understood that the venue was popular with survivors of the earlier tragedy, who enjoyed listening to country music there and found solace in the community.
Speaking after discovering his death, Mr Orfanus' mother issued a desperate plea for gun control.
"Here are my words: I want gun control," Susan Schmidt-Orfanos said. "I don't want prayers. I don't want thoughts."
A US Navy veteran, Mr Orfanus had a thick beard and friendly smile. His friends called him Tel.
Dan Manrique, 33
Dan Manrique was a veteran who had served in the Marines and worked to help others who had left the armed forces.
He worked for charity RWB, which helped support veterans to connect to their communities through physical and social activities.
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"Dan's life was dedicated to serving others, during his military career and beyond," John Pinter, executive director of Team RWB said.
"We offer our deepest condolences to the Manrique family and ask that our Eagles around the world join us in keeping all those impacted by this tragedy in your thoughts and prayers."