FBI director James Comey has told a news conference on the background to the San Bernardino massacre that the bureau’s investigation had “developed indications of radicalisation by the killers and of potential inspiration by foreign terrorist organisations”.
Officials are trying to understand the motives of the killers behind the shootings earlier this week and are scouring every detail of their lives, including a very large volume of electronic evidence that they tried to destroy and conceal, he said.
There was no evidence so far the suspects were part of a large group or network, or members of a cell, he added.
US federal agents earlier said they are investigating the mass shooting, which left 14 dead and 21 wounded in a California social services centre on Wednesday, "as an act of terrorism".
Evidence uncovered
The FBI official in charge of the investigation said the authorities had uncovered evidence that led them to believe that extensive planning had been carried out before the attack.
“We are now investigating these horrific acts as an act of terrorism,” said David Bowdich, assistant director of the FBI in Los Angeles.
Mr Bowdich said investigators were aware of a post on social media website Facebook around the time of the attack pledging allegiance to the leader of the Islamic State militant group.
“We are still continuing to look at that,” he told reporters.
US law enforcement sources, quoted by various US media outlets, said Pakistani woman Tashfeen Malik (27) made the pledge to the jihadist group’s leader, Abu Bakr al-Baghdadi, in a message left on Facebook under an alias.
She apparently later removed the post. She is suspected with her husband of carrying out the mass shooting.
The message, which was recovered by FBI investigators, suggests the attack allegedly carried out by Malik and her husband Syed Rizwan Farook (28) at a San Bernardino social services centre, about 90km east of Los Angeles, was premeditated.
News channel CNN reported, quoting investigators, that the message was posted by Malik during the attack.
Investigators had been examining a possible terrorist link in addition to a workplace grievance by Farook, a devout Muslim and a restaurant inspector for a county health department.
He is alleged to have left his festive party following an argument about religion with a colleague who had denounced the “inherent dangers of Islam”.
Law-enforcement officials cautioned against concluding that the couple were directed by Islamic State, the group behind last month’s attacks in Paris.
Self-radicalised
“At this point, we believe they were more self-radicalised and inspired by a group than actually told to do the shooting,” a law enforcement official told the New York Times.
The FBI has been monitoring the activities of individuals who they believe may be prepared to carry out attacks in the name of Isis.
The radical group had, before the November 13th terrorist attacks in Paris that left 130 people dead, urged supporters to bring the fight to the streets of the US and Europe by murdering civilians at random.
In the wake of Wednesday’s attack, investigators discovered that Farook and Malik had amassed thousands of rounds of ammunition and bomb-making materials at their home. They also appeared to have destroyed computer hard drives, electronic equipment and mobile phones before their attack.
Malik (27) travelled to the US on a Pakistani passport from Saudi Arabia where Farook, a US citizen born in Illinois to Pakistani parents, is said to have met on a dating website.
The couple travelled to the US in July 2014 after spending about a week in Saudi Arabia. Malik entered the country on a K-1 visa that permits foreigners to travel to the US to marry an American.
