The deadly attack happened just before 11 a.m. on Dec. 2, 2015. The suspects stormed into the Inland Region Center and opened fire on a group of employees with the San Bernardino County Department of Public Health, who were gathered for a holiday event.
The county held a moment of remembrance on Tuesday morning to mark the somber date and honor the lives lost. In addition, all flags were flown at half-mast at city and county buildings.
Honoring the victims of 2015 terror attack in San Bernardino
Retired San Bernardino Police Chief recalls the terrorist attack
"I've seen a lot in my career. I've seen a lot of gunshots. I've seen a lot of just terrible crime scenes. That would rank up there with about as gruesome as anything I had seen," said Jarrod Burguan, retired San Bernardino police chief.
Burguan says he distinctly remembers coming across one of the department's detectives as he arrived on scene.
"I remember looking at him, and I'm like, 'What do we have in there?' and he goes 'Oh, it's pretty bad,' and I'm like, 'What does bad mean?'... Does bad mean two, 10? He's like, 'More.'"
Not only was there a massive crime scene to investigate, but the shooters had gotten away. But several tips helped law enforcement identify them.
Soon after, one of the people inside the room at the time of the shooting provided a possible name -- Syed Farook.
"This particular witness had the observation that Syed had been at that event that morning. He had got up and left, which he thought was odd. And then, when the suspects did come in, there was something familiar about the suspect that triggered Syed Farook. So he told one of the officers when he was evacuated that maybe this is somebody that you should look for," Burguan said.
They also got reports of a potential vehicle description -- a black SUV.
That's when a tip came in from a man named Stewart Boden. A tip that would be critical.
"He gets home, sees the news coverage, and realizes, 'Well, I saw a black SUV on my way home.' And Stewart Boden's a very unique guy, memorized the plate. We've all kind of heard that story, right? And he gave that plate to the dispatchers when he called. That came back Enterprise Rental Car, again, we've got investigative analysts in the background, have connections at Enterprise. That call to Enterprise verified that particular plate, that particular car, was rented to Syed Farook," Burguan said.
That's when undercover detectives were sent to the suspect's Redlands apartment.
"In the midst of having eyes on that, out of the side driveway was the matching black SUV that pulled out," Burguan recalled.
Officers then started following the vehicle, and what followed was a fearsome gunfight about a mile and a half from the original scene.
By the time it was over, the suspects had fired more than 80 rounds, and law enforcement officers had fired more than 440.
An officer who was wounded in the gunfight survived.
Islamic terrorists Farook and Tashfeen Malik were dead. So were 14 innocent victims -- so many lives shattered forever.
"I would like to see this process continue to focus on the people who were most impacted by it," Burguan said. People like the Sandefurs, who are still struggling with the impact of their son's death a decade later.
"We never get over it, you just get used to it," Sandefur said.
Family remembers victim Daniel Kaufman 10 years later
"We sure miss him. That's a given. We miss him a lot," said Mark Sandefur of his son, Daniel Kaufman, who was one of the people killed on Dec. 2, 2015.
He and his wife, Julie, often come to the memorial for their son, the infinity loop in Rialto.
Family remembers IE terrorist attack victim 10 years later
A total of 14 trees line the infinity loop, and the tree in the center is dedicated to Kaufman. It started as the seedling of a tree that sprouted from seeds of another tree that Kaufman planted himself when he was in school.
"It's hard to believe it's been ten years," Sandefur said. "It doesn't make for good feelings this time of year."
Kauffman was an employee at the Inland Region Center.
"His job was to teach highly-functioning people with mental disabilities how to become baristas at a coffee shop," Sandefur said.
Kauffman was not part of the holiday event, but was outside, a place he usually wouldn't even have been, but he happened to be late that day.
"Unfortunately, he took an early lunch because he missed his breakfast, and he was sitting out at the picnic table right at the entrance to the area, and he was the first person who was actually shot," Sandefur said.
When news of the terrorist attack started breaking, at first, Kaufman's family felt that they had no reason to worry.
"It had been reported that this had happened at a different location from where he worked, so we never suspected that he was involved with it," Sandefur said.
Hours later, when the suspects were killed in a shootout with law enforcement, Kaufman's parents still had no idea their son was already dead.
"His student, the one who he was teaching, he thought maybe he had been wounded and told us he thought that he was at the hospital. So we got some friends together, and we all made a circle of the hospitals, and as we got to the last one, Loma Lina, the director of Loma Lina, who went and checked all the victims, came back and told us that he wasn't amongst them. That's when we realized we had to go back to the center, where they were gathering people to give information," Sandefur said. "We were standing there and looking around, wondering what was going on, when this guy came up, and he said, 'The coroner will be with you to talk to you in just a minute.' And that was really a shock. We realized that he was one of the victims."
There are several other memorial tree groves for the victims throughout the Inland Empire.
The Sandefurs said they received more than $150,000 in donations.
"We gave scholarships to a girl who wanted to go to medical school. We gave a scholarship to a woman who wanted to be an X-ray technician. The money is all gone now, but all, every single dollar, went to good use," Sandefur said.