SAN BERNARDINO (CBSLA.com) — FBI officials continued to search for clues Tuesday to help determine what led a married couple to carry out a deadly mass shooting at a social services facility in San Bernardino.
During a news conference on Monday, federal law enforcement officials explained Syed Rizwan Farook, 28, and Tasfeen Malik, 27, had been radicalized "for quite some time" and had taken target practice at area gun ranges.
According to CBS News, the man believed to have bought the assault weapons used in the mass killing, Enrique Marquez, has checked into a psychiatric hospital. The FBI is in contact with Marquez for questioning.
Federal officials said the guns -- which were purchased between 2007 and 2012 -- were allegedly reconfigured to be more powerful after they were legally purchased in California.
Authorities have also disclosed that Farook's co-workers at the county health department underwent "active shooter" training in the same conference room a year before the rampage took place.
As county employees continue return to work, security has been increased at all county facilities.
On Friday, Asst. FBI Regional Director David Bowdich explained federal officials are investigating this case as an act of terrorism.
According to the FBI, Farook and Malik carried out Wednesday morning's deadly shooting at the Inland Regional Center, located in the 1300 block of South Waterman Avenue. The married couple appeared to have been supporters or advocates of terrorist groups in the Middle East.
The married couple carried in legally purchased semiautomatic weapons, along with handguns, and opened fire upon workers while the San Bernardino County Department of Public Health was holding a holiday banquet within the conference room of the building.
Fourteen people were killed and 22 others were injured in the attack.
The Coroner's Office has identified all of the deceased victims. Funeral arrangements have not yet been announced for the deceased victims.
Following the shooting, Farook and Malik were fatally shot during a stand-off with police in the city of Redlands.
Authorities seized AR15 style rifles, two pistols, thousands of caliber rounds, a large arsenal of explosive devices made from Christmas tree lights and radio-controlled toys and digital evidence including thumb drives.
A preliminary investigation revealed the couple came into the U.S. in July 2014.
Pakistani-born Malik, who entered the county on a K-1 visa, is believed to have pledged her allegiance to the ISIS leader Abu Bakr al Baghdadi in a Facebook post around the same time the attack was carried out, according to CBS News.
Farook, who worked as an inspector for the San Bernardino County Environmental Health Department, had traveled to Saudi Arabia to apparently attend the Hajj pilgrimage.
While he has not been found on any terror watch lists, officials believe Farook was radicalized prior to committing the senseless and violent acts. He was reportedly in contact with people who may be linked to terrorism overseas.
Farook and Malik's 6-month-old baby girl remains in the custody of the Department of Children and Family Services. A custody hearing was held Monday, however, it remains unclear if Farook's family members were granted permission to file for adoption.
Officials continue to stress that there is no credible threat of danger to the community at this time.
The FBI has established a national hotline for the public to report any suspicious activity. Please call (800) 225-5324 and select option four.
Arrowhead United Way and the San Bernardino County Board of Supervisors have set up a relief fund. To make a donation, send a text message stating "SBUNITED" to 71777. Checks may be made payable to SBUNITED and mailed to Arrowhead United Way, 646 North D St., San Bernardino, CA 92401.
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