Previous update: KNBC is reporting at least 14 killed in mass shooting at Southern California Social Services Facility; Suspects at large.
At least 14 people were killed and one or more suspects were in custody Wednesday when up to three gunmen on a "mission" barged into a holiday party in a California conference room and unleashed a bloodbath, law enforcement sources told NBC News.
The gunman or gunmen fled in a black SUV after the shooting about at 11 a.m. (1 p.m. CT), police said.
About 4½ hours later, multiple police cars were involved in a high-speed chase nearby with three people in a dark truck or SUV, law enforcement sources told NBC News. Two of the suspects were shot, the sources said — one was killed and the other was wounded in the chest.
At least one of the suspects was in custody Wednesday afternoon, the sources said.
In addition to the 14 dead:
At least 10 of 17 wounded are in critical condition.
Police arrested at least one suspect after shootout hours later.
The shooting erupted during a holiday party in a conference room.
Federal agencies are assisting the investigation.
Seventeen other people were wounded when the shooting started inside the Inland Regional Center in San Bernardino, about 55 miles east of downtown Los Angeles, police said.
Authorities said 10 of the 17 injured were taken to hospitals in critical condition. Fire Chief Tom Hannemann said three people were in serious condition.
It appeared to be the worst mass shooting since the December 2012 slaughter of 20 first-graders and six staffers at Sandy Hook Elementary School in Newtown, Connecticut.
"These people came prepared to do what they did as if they were on a mission," San Bernardino Police Chief Jarrod Burguan said. "They were armed with long guns, not with handguns."
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Previous story: Police say "up to 14" people are dead and more than a dozen more wounded following a shooting in San Bernardino, California.
Police are searching for up to three suspects, described as white males wearing tactical gear, by witnesses and victims.
The shooting took place at Inland Regional Center, a facility that provides services to the developmentally disabled.
Firefighters evacuated the wounded using a pickup truck and set up a triage area nearby.
At least one of the suspects was believed to be wearing tactical gear, the NBC affiliate KNBC reported.
"I know we do have some fatalities," Lt. Richard Lawhead of the San Bernardino police told KNBC. "But I don't know the numbers."
Firefighters set up a triage area near the Inland Regional Center on the South Waterman Avenue, where they were treating the wounded on the street and loading others into waiting ambulances for treatment at nearby Loma Linda Medical Center.
Some were transported in the back of pickup trucks.
San Bernardino police "confirmed an active shooter in the area of Orange Show Rd/ Waterman Ave near Park center," according to the San Bernardino County Sheriff's Department.
Up to three people were suspected in the shooting, sheriff's officials said.
The shooting broke out at the Inland Regional Center, which serves more than 31,000 people with developmental disabilities in San Bernardino County and neighboring Riverside County, according to the center's "About" page on its website. It says it's the largest of California's regional centers, and is "a nonprofit, private community-based agency that is proud to help obtain services and support for our constituents."
San Bernardino is about 60 miles from Los Angeles.
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