Updated on December 3 at 3:08 p.m. EST

Here’s what we know Thursday afternoon:

—The shooters have been identified by police as 28-year-old Syed Rizwan Farook and 27-year-old Tashfeen Malik. They were married and had a six-month old daughter. Both shooters were shot and killed by police officers.

—At least 14 people are dead and 21 wounded, up from 17 on Wednesday, in the attack, which occurred at the Inland Regional Center in San Bernardino.

—Police recovered a haul of weapons and ammunition both from the vehicle in which Farook and Malik were found and at a home they had rented.  

—Police are investigating terrorism and a workplace dispute as possible motives.

The married couple who killed 14 people and wounded 21 others at a social-services center in San Bernardino, California, fired up to 75 rounds in the attack, left behind three pipe bombs that had been rigged together, and had thousands of rounds of ammunition on them and at their home, officials said.

San Bernardino Police Chief Jarrod Burguan said at a news briefing Thursday that the couple had more than 1,600 bullets when they were killed in their SUV. Authorities discovered more than 3,000 rounds of ammunition, as well as 12 pipe bombs, and other tools, he said.

“There was obviously a mission here,” David Bowdich, assistant director of the FBI’s Los Angeles office, said at the news briefing. “We know that. We do not know why. We don’t know if this was the intended target or if there was something that triggered him to do this immediately.”

Bowdich refused to speculate on a motive for the shooting, but said authorities had not ruled anything out, including terrorism or whether the attack at the Inland Regional Center was prompted by a workplace dispute.

Speaking from the Oval Office, President Obama echoed those comments, and added: “We’re going to get to the bottom of this.”

Farook was an environmental engineer who worked with the San Bernardino County Health Department. He had been attending a holiday party for the department at the Inland Regional Center on Wednesday, left after some sort of dispute, and returned with Malik at about 11 a.m. local time carrying weapons, Burguan said. All four guns were legally purchased, he said Thursday. Three pipe bombs rigged together, discovered at the scene, failed to detonate, Burguan said.  

Bowdich said Farook, who was born in Illinois, had traveled overseas in recent years, and had visited Pakistan, from where his parents emigrated. He returned in July 2014 with Malik, who traveled on a Pakistani passport with a fiancee visa. The couple had a 6-month-old daughter. Farook’s colleagues told the Los Angeles Times he had visited Saudi Arabia and had returned with Malik.

On Wednesday night, Farhan Khan, who is married to Farook’s sister, expressed his condolences to the victims, who have not yet been identified.

“I have no idea why he would do something like this,” Khan said. “I have absolutely no idea. I’m in shock myself.”

Police received word of the shooting at about 11 a.m. Wednesday. They secured the scene and evacuated the sprawling facility, which provides services for people with disabilities. The suspects fled in a dark-colored SUV, Burguan said Wednesday. On Thursday, he said police received a tip about Farook leaving the party. They then found he had rented a Ford Expedition, which marked the description of the vehicle the suspects were seen leaving in. That vehicle was due to be returned on Wednesday.

The information led about 300 local, county, state, and federal law enforcement officials to the nearby town of Redlands, where Farook and Malik rented a home. It’s unclear if they lived there, Burguan said. Officers and the couple exchanged fire. Farook and Malik fired up to 75 rounds at them, Burguan said. Officers fired 380 rounds at the suspects, killing them.

Two officers were wounded: One was shot in the left leg; the other received cuts; neither injury is life-threatening. News helicopter footage Wednesday showed the scene at a residential street, where dozens of heavily armed police officers had gathered. A dark-colored SUV was stopped in the middle of the street, its windows blown out.

The FBI is leading the investigation, Obama said, and is being assisted by local agencies. The Loma Linda Medical Center said of the five victims in its care, two are in critical condition and three in fair condition.

A suspect who was detained on Wednesday was released, Burguan said, after it was determined he had no connection to the shooting.

We will update this story as we learn more.

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