SAN BERNARDINO, Calif. -- Two suspects involved in a mass shooting at a Southern California social services center, killing 14 people and wounding more than a dozen others, are dead, police say. A third possible suspect has been detained.

San Bernardino Police Chief Jarrod Burguan said the two suspects, one male and one female, are dead after engaging in a shootout with police hours after the initial attack. The pair had been spotted in a dark SUV as police investigated a residential area near the shooting location.

An undated photo from an online dating website shows Syed Rizwan Farook, who has been identified to CBS News as one of the suspects in the Dec. 2, 2015 shooting at the Inland Regional Center in San Bernadino, Calif. CBS News

Late Wednesday night, Burguan identified the suspects as Syed Rizwan Farook, 28, and Tashfeen Malik, 27. They were believed to be the only shooters.

Farook worked as an environmental specialist at the San Bernardino County public health department, which was holding a holiday party Wednesday at the Inland Regional Center. Burguan said authorities believe Farook attended the event but left after a dispute, and returned later to open fire.

Farhan Khan, Farook's brother-in-law, stood alongside local Muslim leaders late Wednesday evening expressing his sadness for the victims of the attack at the Inland Regional Center.

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"Why would he do that? Why would he do something like this? I have absolutely no idea, I am in shock myself," Khan, who is married to Farook's sister, told reporters. He said he last spoke to Farook about a week ago.

Kahn said Farook and Malik had been married for about two years and had a six-month-old daughter. They lived with his mother, who was caring for the child today.

Police said a person was detained who was seen running near the gunbattle between the suspects and the officers. Burguan said it was not clear if that person is connected to the shooting. After the shooting, police conducted a search of the neighborhood and declared it safe.

A police officer was injured in the gunfire with the suspects, but authorities say his injuries are non-life threatening.

The shooting at the Inland Regional Center was the deadliest mass shooting in a nation all too familiar with them since 2012, when a man killed 26 children and adults at a school in the Newtown, Connecticut.

U.S. official tells CBS News this is a joint investigation between the FBI and the local police until a motive can be established.

The FBI says it's a possibility that the shooting is "terrorism," though it was too early to make any definitive conclusions.

A federal law enforcement official told CBS News' senior investigative producer Pat Milton that the two assault weapons found in suspects' SUV were AR-15 style rifles. There were also two pistols found in the SUV. Investigators are tracing the weapons to determine if they were legally purchased, where and when.

Each of the dead suspects were dressed in actual tactical clothing and each had multiple magazines of ammunition attached to the military style clothing that they were wearing.

The suspects were "loaded with magazines for a gunfight," Meredith Davis, a spokeswoman with ATF, told CBS Los Angeles.

The official said that a piece of metal pipe was thrown from the SUV while the chase was underway but that proved not to be an explosive device.

Police said three explosive devices similar to pipe bombs were found at the center. Milton reports that the contents of the explosive devices found at the scene of the shooting is being analyzed for content and construction by bomb techs.

Meanwhile, police are serving a search warrant on a home in Redlands, California, in connection with the shooting. Law enforcement officers are calling for people to come to the front door of a home there.

One of them called out: "This is the FBI." Officers in riot gear, a bomb squad unit and armored vehicles are outside Wednesday night. They appear to have brought in robot devices. It's unclear if anyone is inside the home.

City spokesman Carl Baker says Redlands police are assisting San Bernardino police in the search connected to the San Bernardino shooting.

Burguan said upwards of 14 people were killed and 18 injured in the shooting. The number of fatalities are subject to change.

Several hundred others were in building at the time and not injured.

The Inland Regional Center provides social services for children and adults with intellectual and developmental disabilities.

The attack took place in a conference area where the San Bernardino County Department of Public Health was renting space to hold a banquet, said Marybeth Feild, president and CEO of the center. She said the building houses at least 25 employees as well as a library and conference center.

"48 Hours" Crimesider reporter Erin Donaghue spoke with Sandra Wood, interim executive director of the Inland Empire Lighthouse for the Blind, a school for visually impaired adults located about 200 feet from the Center.

Wood said she was on the second floor of her building around 11:15 this morning when she heard what sounded like automatic gunfire. She said she heard about 25 to 30 rounds, followed by more gunfire.

"You could tell the person stopped and re-loaded and started again," Wood said.

Terry Petit says he got a text from his daughter saying she was hiding after gunfire erupted at the social services facility in Southern California where she works.

Petit choked back tears Wednesday as he read the texts for reporters outside Inland Regional Center.

He says she wrote: "People shot. In the office waiting for cops. Pray for us. I am locked in an office."

Police searched people filing out of a building with their hands up before they reunited with loved ones. Other people were seen being wheeled away on gurneys.

Paul Lacroix said his son was able to escape after gunfire erupted. Lacroix told reporters Wednesday that his son texted him and told him alarms started going off and they got word there was shooting.

He said his son was sheltered with a group of people before they managed to get out. Lacroix said his son and colleagues were ordered to exit with their arms up and nothing in their hands.

California Gov. Jerry Brown says the shooting is a brutal attack.

He said in a statement that "California will spare no effort in bringing these killers to justice." The governor was scheduled to light the Capitol Christmas tree Wednesday evening, but his office said the ceremony will be canceled.

President Obama has been briefed by his Homeland Security Advisor Lisa Monaco about the shooting and has asked to be updated on the situation as it develops.

"We don't know that much yet" about the circumstances in San Bernardino, Mr. Obama said in an interview Wednesday afternoon with CBS News' Norah O'Donnell.

"The one thing we do know is that we have a pattern now of mass shootings in this country that has no parallel anywhere else in the world," he continued.

Stores, office buildings and at least one school were locked down in the city of 214,000 people about 60 miles east of Los Angeles.

This story will be updated as more information is available.