Rizwan Farook and Tashfeen Malik

Farook was born in Chicago, Illinois,[11][12][13] and was a U.S. citizen. His parents had emigrated from Pakistan.[14]

According to sources, Farook had a "troubled childhood"[15] and grew up in an abusive home in which his father was often violent towards his mother.[16][17][18] Farook grew up in Riverside, California, and attended La Sierra High School, graduating in 2004, one year early.[19][20] He attended California State University, San Bernardino, and received a bachelor's degree in environmental health in either 2009 or 2010.[19][20][21] He was a student for one semester in 2014 at California State University, Fullerton in their graduate program for environmental engineering, but never completed the program.[19]

Farook had a profile on the dating website iMilap.com, in which he listed backyard target practice as a hobby. A lawyer for Farook's family also said that he would go to firing ranges by himself.[22]

Farook worked as a food inspector for the San Bernardino County Department of Public Health for five years before the shooting.[23][24][25] From July to December 2010, he was a seasonal employee for the county. He was hired as an environmental health specialist trainee on January 28, 2012, and became a permanent employee on February 8, 2014.[19] Coworkers described Farook as quiet and polite, and said that he held no obvious grudges.[26]

According to family members and coworkers, Farook was a devout Sunni Muslim, and traveled to Saudi Arabia several times, including to complete the hajj in 2013.[14][27] Farook attended prayers at the Islamic Center of Riverside twice a day, in the mornings and the evenings, according to an interview in The New York Times with Mustafa H. Kuko, the center's director. According to the Times, Farook stood out as especially devout and "kept a bit of a distance" from other congregants.[28] During that time, according to friends, he never discussed politics. Farook abruptly stopped going to the mosque in 2014 following his marriage.[29]

The Italian newspaper La Stampa reported that Farook's father said that his son "shared the ideology of Al Baghdadi to create an Islamic state" and that he was fixated with Israel.[30] A spokesperson for the Council on American–Islamic Relations (CAIR) later claimed the father did not recall making these statements about his son.[31]

Malik was born in Pakistan, but lived most of her life in Saudi Arabia and the U.S.[11][24][32] Her original hometown was Karor Lal Esan, 450 kilometers (280 mi) southwest of Islamabad, Pakistan.[33] Her landowning family was described as politically influential in the town.[34]

Malik returned to Pakistan to study pharmacology at Bahauddin Zakariya University in Multan, beginning the program in 2007 and graduating in 2012.[34][35][36] Saudi Interior Ministry spokesman Major General Mansour Al-Turki denied reports that Malik grew up in his country, saying that she visited Saudi Arabia only for a few weeks in 2008 and again in 2013.[37] The city of Multan has been linked to jihadist activity.[38]

While in Multan, Malik attended the local center of the Al-Huda International Seminary, a women-only religious academy network with seminaries across Pakistan and branches in the U.S. and Canada that was founded in 1994.[36][38][39] The school is aligned with the Wahhabi form of Sunni Islam.[39] According to school records, Malik enrolled in an eighteen-month Quranic studies course with Al-Huda on April 17, 2013, and left on May 3, 2014, telling administrators that she was leaving to get married. Malik expressed an interest in completing the course by correspondence, but never did so.[36]

According to experts, Al-Huda "draws much of its support from women from educated, relatively affluent backgrounds."[36] Faiza Mushtaq, a Pakistani scholar that studied the organization, said that "these Al-Huda classes are teaching these urban, educated, upper-middle-class women a very conservative interpretation of Islam that makes them very judgmental about others around them." According to the Los Angeles Times, Al-Huda seminaries promote anti-Western views and hard-line practices in a fashion that "could encourage some adherents to lash out against non-believers."[40] The New York Times reported that the institute "teaches a strict literalist interpretation of the Quran, although it does not advocate violent jihad."[41] An Al-Huda administrator from the head office in Islamabad said that terrorism "is against the teachings of Islam" and that the school's curriculum did not endorse violence.[40]

According to one of Farook's coworkers, Malik and her husband married about a month after he traveled to Saudi Arabia in early 2014; the two had met over the Internet.[9][26] Malik joined Farook in California shortly after their wedding. A U.S. marriage certificate reported their marriage in Riverside on August 16, 2014.[42] At the time of her death, Malik and Farook had a six-month-old daughter.[25][43][44]

Malik entered the United States on a K-1 (fiancée) visa with a Pakistani passport.[14][27][45] According to a State Department spokesman, all applicants for such visas are fully screened.[46] Malik's application for permanent residency (a "green card") was completed by Farook on her behalf in September 2014, and she was granted a conditional green card in July 2015.[45] Obtaining such a green card would have required the couple to prove that the marriage was legitimate.[14][45] As is standard practice,[14][45] as part of her visa application with the State Department and application for a green card, Malik submitted her fingerprints and underwent "three extensive national security and criminal background screenings" using Homeland Security and State Department databases. Malik also underwent two in-person interviews, the first with a consular officer in Pakistan and the second with an immigration officer in the U.S. after applying for a green card.[41] No irregularities or signs of suspicion were found in the record of Malik's interview with the Pakistani consular officer.[47]

Malik reportedly had become very religious in the years before the attack, wearing both the niqab and burqa while urging others to do so as well.[48][49] Pakistani media reported that Malik had ties to the radical Red Mosque in Islamabad, but a cleric and a spokesman from the mosque vehemently denied these claims, saying that they had never heard of Malik before the shooting.[49][50] Malik's estranged relatives say that she had left the moderate Islam of her family and had become radicalized while living in Saudi Arabia.[50][51] Saudi Interior Ministry spokesman Al-Turki rejected this claim, stating that Saudi officials received no indication that Malik was radicalized while living there.[52]

On December 16, 2015, FBI Director James B. Comey said, "We can see from our investigation that in late 2013, before there is a physical meeting of these two people [Farook and Malik] resulting in their engagement and then journey to the United States, they are communicating online, showing signs in that communication of their joint commitment to jihadism and to martyrdom. Those communications are direct, private messages."[53][54]

Early reports had erroneously stated that Malik had openly expressed jihadist beliefs on social media, leading to calls for U.S. immigration officials to routinely review social media as part of background checks, which is not part of the current procedure.[41] Comey subsequently clarified that the remarks were "direct private messages" that were not publicly accessible and that "So far, in this investigation, we have found no evidence of posting on social media."[53]

Comey said that the FBI's investigation had revealed that Farook and Malik were "consuming poison on the Internet" and both had become radicalized "before they started courting or dating each other online" and "before the emergence of ISIL."[53][55] As a result, Comey said that "untangling the motivations of which particular terrorist propaganda motivated in what way remains a challenge in these investigations, and our work is ongoing there."[53]

The four guns used by the shooters. Released by the San Bernardino County Sheriff's Department.

Farook and Malik used two .223-caliber semi-automatic rifles, two 9 mm caliber semi-automatic pistols, and an explosive device in the attack.[1][2][14] The rifles used were variants of the AR-15: one was a DPMS Panther Arms A15, the other was a Smith & Wesson M&P15.[14][66]

The two rifles were purchased by Enrique Marquez Jr.,[67][68] a next-door neighbor of Farook's until May 2015[69] who is related to him by marriage.[70] After their purchases, the rifles were illegally transferred to Farook. The two pistols were legally purchased by Farook from federally licensed firearms dealers in Corona, California, in 2011 and 2012.[71][72][73] One of the handguns was a Llama Model XI-B and the other was a Springfield Armory XD Bi-Tone.[2]

Tactical belt used by one of the shooters. Released by the San Bernardino County Sheriff's Department

The couple altered the guns: there was a failed attempt to modify the Smith & Wesson rifle to fire in fully automatic mode, they made a modification that defeated the ban on detachable magazines, and they used a detachable high-capacity magazine. California laws limit magazines to a maximum of ten rounds, and prior to this attack the magazine had to be fixed by a recessed button mechanism to the rifle and require a tool such as a bullet, pen, or other implement to remove it, thereby creating a delay in the rate at which spent magazines can be replaced.[2][74] According to the Bureau of Alcohol, Tobacco, Firearms and Explosives, the modifications made the guns illegal assault weapons.[14] The couple also taped magazines together to make switching them out easier. They had a total of 2,363 rounds (1,879 for the rifles and 484 for the handguns) with them at the time of the shootout.[75]

The explosive device left at the Inland Regional Center comprised three explosive devices connected to one another. It was contained inside the backpack left by Farook during the departmental event. The devices were described as pipe bombs constructed with Christmas lights and tied together, combined with a remote-controlled car that was switched on. The poorly constructed devices failed to explode.[12][76][77]

The large stockpile of weapons used by Farook and Malik led investigators to believe that they intended to carry out further attacks.[78] An examination of digital equipment recovered from their home suggested that the couple was in the final planning stages of a much larger attack.[79]

After law enforcement sources confirmed that Farook spent time on November 29–30, 2015, at the Riverside Magnum Shooting Range, about 25 miles (40 km) away from the couple's Redlands home, the FBI obtained surveillance video from the range. During these visits, one lasting several hours, Farook shot an AR-15 and a pistol, which he had brought to the range.[80] One of the paper torso silhouette targets used in the video was later recovered from the couple's SUV following their deaths.[81]

Two weeks before the shooting, Farook took out a loan of US$28,500 which was deposited in his bank account. The San Francisco-based online lender Prosper Marketplace made the loan to Farook; Prosper evaluates borrowers and the loans are originated by a third-party bank, the Salt Lake City-based WebBank.com.[82][83] On or about November 20, 2015, Farook withdrew US$10,000 in cash, and later on two US$5,000 transfers were made to what appears to be Farook's mother's bank account. Investigators were exploring the possibility that the US$10,000 was used to reimburse someone for the purchase of the rifles used in the shooting.[82] WebBank said that it was fully cooperating with the investigation.[84]

After the attack, a witness recognized Farook and identified him to police.[88][92][108] When officers responded to Farook and Malik's Redlands home, both fled in a sports utility vehicle (SUV), resulting in a police pursuit.[1][8][96][109] At least one fake explosive was thrown at the police during the chase.[1][96]

The chase ended in a suburban neighborhood about 1.7 miles (2.7 km) away from the scene of the initial attack. There, Farook and Malik exchanged gunfire with officers.[8] The gunfire lasted for around five minutes before both Farook and Malik were killed by police bullets.[8][9][10] Farook died from 26 gunshot wounds, sustained mostly in the legs and including one in the chin where the bullet fragmented into his neck. Malik died from fifteen gunshot wounds, thirteen to the body and two to the head.[75]