The FBI announced Friday that it was formally taking charge of the investigation into the mass shooting in San Bernardino, California that killed 14 and wounded 21, on the assumption that the horrific massacre was a terrorist attack.

“This is now a federal terrorism investigation led by the FBI,” said FBI Director James Comey. “And the reason for that is the investigation so far has developed indications of radicalization by the killers and of potential inspiration by foreign terrorist organizations.”

Comey said that evidence uncovered so far suggested that two suspects—both slain by police—Syed Farook, a 28-year-old county health inspector, and his 27-year-old wife, Tashfeen Malik, had been “radicalized,” but that there was no indication that they were part of any broader group.

The FBI director added that there was there was still “a lot of evidence that doesn’t quite make sense.”

The most widely cited indication of “radicalization” was a Facebook posting allegedly made immediately after the attacks by Malik, under an alias, swearing allegiance to the Islamic State of Iraq and Syria (ISIS). The FBI has also claimed that Farook had been in contact two years ago with Islamist elements, including the Al Nusra Front in Syria, an Al Qaeda affiliate that enjoys virtual state sponsorship from one of Washington’s closest allies, Qatar.

The other source of the alleged “radicalization” under investigation is trips made by Farook to Saudi Arabia, Washington’s other closest ally in the Arab world, along with his wife’s previous residence in the kingdom. Pakistani family members of Malik’s father have told the media that they were shocked by how hardline and conservative he had become in his beliefs after moving to Saudi Arabia, which is the ideological font, as well as a major financial sponsor, of Islamist terrorism.

The corporate media and large sections of the political establishment had been pressing for the mass shooting to be labeled as a terrorist attack from the moment it emerged that the two suspects, the US-born Farook and his wife, who was from Pakistan, were both Muslim. These layers are anxious to exploit the tragedy to further Washington’s reactionary agenda of aggressive war abroad, together with police state repression and anti-immigrant chauvinism at home.

Unlike any other act of terrorism committed on US soil, however, in this case the victims were all co-workers of Farook, with whom he was attending a holiday office party. They were all well known to him, suggesting that the attack may have more in common with the kind of workplace mass killings that happen on a staggeringly regular basis in America.

According to the Bureau of Labor Statistics’ Census of Fatal Occupational Injuries (CFOI), there were 14,770 workplace homicide victims between 1992 and 2012, an average of over 700 such killings every year.

At the same time, unlike any other workplace shooting on record, Farook carried out the killings together with his wife, after dropping off their infant daughter with his mother. Such actions and the evident planning that went into assembling an arsenal of guns, ammunition and explosives, indicate an ideological element in the crime.

The lawyer for Farook’s family, David Chesley, cautioned against trying to link the killings to international terrorism. Speaking to the press Friday, he said that the FBI indicated to him that they had been “totally stumped” and “totally frustrated” in their attempts to link a motive for the shootings to international Islamist terror.

Chesley said that there were some suggestions that the violence had been “related to his [Farook’s] work, that he was a disgruntled employee.” He added that “some of his coworkers made remarks about his beard.”

Coworkers have reported that Farook had been involved in a heated argument about Islam and Israel two weeks before the massacre with a fellow worker killed in the attack, Nicholas Thalasinos, who identified himself with Messianic Judaism and reportedly espoused right-wing political views.

Thalasinos’ widow told the New York Times: “My husband was very outspoken about ISIS and all of these radicalized Muslims.”

Witnesses at the holiday party said that the couple shot Farook’s supervisors first.

What suggests itself in the San Bernardino massacre is a kind of hybrid attack, the result of a toxic mixture, the interaction of a whole series of pathologies spawned by American capitalism both at home and abroad.

That individuals are even attracted to the reactionary ideology of Islamic fundamentalism is a measure of the staggering level of social alienation that exists within far broader layers of the population. Farook and his wife have been described by family and neighbors as quiet and introverted. Clearly, however, unseen by even those closest to them, there was beneath the surface seething bitterness, anger and alienation.

The desperate search for some simplistic international terrorist link to the tragedy in San Bernardino serves to obscure the deeper causes. The alienation of large numbers of people from a social order dominated by extreme inequality and exploitation, combined with endless war abroad and rampant police violence at home, are the real roots of the epidemic of mass shootings that are emblematic of US society.

At the same time, Islamism has been cultivated by US imperialism as a reactionary political instrument, from the CIA-backed war in Afghanistan in the 1980s through to the ongoing war for regime change in Syria. To the extent that it now produces horrors within the US, it is very much a case of US imperialism’s chickens coming home to roost, with average working people left to pay the terrible price.

A critical question posed by the San Bernardino shootings is: Why are there no countervailing democratic tendencies within American society against the influence of such reactionary ideologies? This is bound up with both the ever-increasing monopolization of economic and political power by a financial oligarchy and the endless crimes carried out by US imperialism abroad.

Within barely a day of the San Bernardino shooting, US politicians moved to exploit the killings as a means of scapegoating immigrants. On Thursday, Republican Senators Ted Cruz (Texas) and Jeff Sessions (Alabama) made public a letter to the Obama administration demanding the immigration records of Farook, Malik and their relatives in advance of a Congressional vote on legislation that includes funding for the settlement of Syrian refugees and other immigration programs.

That Farook was an American citizen born in Chicago and raised in southern California didn’t faze the two senators, who demanded the immigration records of his parents, who are in no way implicated in the attack and came to the US decades ago. Their aim is to prevent any of those fleeing the carnage and destruction unleashed by US imperialism in the Middle East from receiving asylum in the US.

The media has responded to the events in San Bernardino with a relentless drive to whip up fear and hysteria while promoting war and fomenting anti-Muslim bigotry. The Washington Post, a leading advocate of an escalation of the US military intervention in Iraq and Syria, declared in an editorial Friday that the shootings—whose real motives are far from clear—demonstrated the need “for the United States to redouble its resolve to destroy the Islamic State and other barbarously radical Islamist groups.”

The New York Post, meanwhile, covered its front page Thursday with a photograph of bloodied victims and a screaming headline reading “Muslim Killers.”

The media frenzy surrounding the San Bernardino shooting assumed bizarre and repulsive dimensions Friday when the landlord of the dead suspects, reportedly paid $1,000 by TV producers, opened up their apartment to dozens of reporters and camera crews, who swarmed in, pawing through everything from scattered papers to their baby’s dolls and pampers.