SAN BERNARDINO, Calif. (MEDIA GENERAL/AP) – A husband and wife stormed a social services center for the disabled in San Bernardino, Calif., Wednesday, firing as many as 75 rounds from assault-style rifles at public health workers gathered for a holiday banquet.

The massacre that unfolded around 11 a.m. left 14 people dead and at least 21 others injured.

The suspects, Syed Farook, 28, and Tashfeen Malik, 27, were wearing assault-style clothing when they entered the southern-most building of the Inland Regional Center. They carried out the attack after dropping off their infant daughter at a family member’s house but their motive remains unknown.

The suspects fled the scene in a black SUV following the rampage but didn’t leave the San Bernardino area.

They were killed just a few hours later following a police pursuit and gun battle with officers that played out in the middle of a residential street not far from the site of the massacre.

Twenty-three officers from seven different agencies fired approximately 380 rounds at the suspects. Police said the suspects fired 76 rounds back. Nearly 2,000 ammunition rounds were found on the suspects and in their SUV.

Two officers were injuried in the melee. One suffered a gunshot wound to the left leg but was expected to be released from the hospital Thursday. Another sustained cuts to his leg.

A third person seen running from the area was detained but he is not believed to have been involved in the shooting.

Chief Burguan said late Wednesday that earlier witness accounts that there were three shooters were probably wrong.

“We are reasonably confident at this point that we have two shooters and we have two dead suspects,” he said.

The mass shooting took place in a conference area inside the Inland Regional Center where the San Bernardino County Department of Public Health was hosting an employee holiday party.

Chief Burguan said the suspects entered through an unlocked door and fired 65 to 75 rounds.

He said it’s unlikely any one person was targeted. “They sprayed the room with bullets,” Burguan added.

Authorities later found a 3-in-1 pipe bomb rigged to a remote control car and four high-capacity rifle magazines left behind by the suspects.

Farook worked as a restaurant inspector for the health department, and attended the holiday banquet before abruptly leaving.

Co-worker Patrick Baccari told the Associated Press he was sitting at the same table as Farook, who suddenly disappeared, leaving his coat on his chair.

Baccari said when the shooting started, he ran to a bathroom. He suffered minor wounds from shrapnel slicing through the wall.

Baccari described Farook as reserved and said he showed no signs of unusual behavior.

Farook was born in the United States but had recently traveled to Saudi Arabia. According to the Baccari, he returned with a wife and later grew a beard.

The FBI is still investigating Malik’s background. They know she entered the United States in July 2014 with Farook. The two married and had a baby girl six months ago.

Police and the FBI are looking at workplace violence and terrorism as possible motives but wouldn’t elaborate.

In speaking from the Oval Office Thursday, President Barack Obama said it’s possible the shooting was related to terrorism but there could also be mixed motives.

The president assured Americans that authorities will get to the bottom of what happened.

The couple’s young daughter was dropped with relatives before the shooting. Hussam Ayloush, executive director of the Council on American-Islamic Relations, spoke with the family who said the couple told them they had a doctor’s appointment.

“They came prepared to do what they did, as if they were on a mission,” Chief Burguan said.

A few hours later, authorities were tipped off on a possible suspect location, a townhome in neighboring Redlands, Calif., just seven miles from the Inland center.

Farook and Malik were listed on the rental agreement although it’s unclear if they actually lived there.

It’s from that home where officers spotted what was later determined to be the suspects’ SUV and from where the pursuit ensued.

According to CNN reports, Malik was driving the SUV while Farook was shooting from the passenger seat. An item later determined to be a fake bomb was thrown from the vehicle.

Thursday, Chief Burguan said Farook had rented the SUV three or four days earlier and it was due to be returned Wednesday.

Authorities returned to the townhome Wednesday night and neighbors in the complex were told to shelter in place. A bomb squad swept the home with robots and Thursday morning, a black sedan parked outside the home was also searched.

In total, the search yielded 12 pipe bombs, hundreds of tools and bomb making materials in addition to thousands of rounds of ammunitions for rifles, handguns and long guns.

When asked if they were planning another attack, Chief Burguan said, “We don’t know. They were equipped for another round. We intercepted them.”

Farhan Khan, who is married to Farook’s sister, expressed shock and condemned the violence. He said he last talked to his brother-in-law about a week ago, adding he had “absolutely no idea why he would do this.”

The identities of those killed weren’t immediately released although the local sheriff’s office planned to begin releasing names on Thursday.

Of the injured, 10 were hospitalized in critical condition as of Thursday morning, according to San Bernardino Fire Chief Tom Hannemann, and three were in serious condition. Others had been treated and released.

The mass shooting is the worst in the U.S. since Sandy Hook in December 2012. Twenty-six people were killed in the shooting at the Connecticut elementary school, including 20 children.

President Obama urged the country to take steps to reduce mass shootings, including stricter gun laws and stronger background checks.

Federal authorities said that the two handguns used in Wednesday’s rampage were purchased legally by Farook. It’s unclear who purchased the assault rifles or how the suspects obtained them, but they were purchased legally.The Associated Press contributed to this report.