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.
CBS News reports that one of the possible suspects is named Syed Farook.
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.
As for a motive, there are reports that one of the shooters may have been at the building for a party, left and returned to shoot. These reports are being checked out, the official said.
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 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.
Burguan also said at a news conference Wednesday evening that authorities found what they believe is an explosive device at the Inland Regional Center. Bomb squads were working on it.
Milton reports that the contents of the explosive device 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.
City spokesman Carl Baker says Redlands police are assisting San Bernardino police in the search connected to the San Bernardino shooting.
An Associated Press reporter watched as a half-dozen vehicles carrying helmeted police drove into the area. One officer carrying an assault rifle ordered reporters to clear the area, and an armored vehicle parked outside a row of homes.
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. She 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.
Wood said she immediately moved away from the windows, called 911 and made an announcement to the school over an intercom telling students to stay where they were.
She said there are about 60 adults at the school now -- she said people are worried and the mood is tense, but everyone is safe. She said the school was on lockdown.
"They're telling us don't let anybody in, don't let anybody out," she said. "Everyone is worried and scared, but we are safe."
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.
© 2015 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.