No evidence of a marriage that killed 14 people in California this month were part of a terrorist cell, the FBI chief said Wednesday, echoing the views of researchers that the couple was inspired by, more organized by the Islamic State.

The Islamic militant group has “revolutionized” terrorism to try to inspire this kind of small-scale attacks, said FBI Director James Comey, highlighting the group uses social media, encrypted and skillfully produced propaganda to recruit followers in communications all the world.

“” Your parents Al Qaeda was a very different model to the threat we face today, “Comey told a terrorism conference in New York.

However, he said that while the perpetrators of the December 2 shooting in San Bernardino, California – Rizwan Syed Farook, 28 and Tashfeen Malik, 29 – had expressed their support for “jihad and martyrdom” in private communications, never so they did on Social media.

Comey said the Federal Bureau of Investigation currently has “hundreds” of research in 50 US states involving possible plots inspired Islamic state.

His comments came as Americans are nervous two weeks after the attack of San Bernardino. Islamic State is based in Iraq and Syria, where it controls a large area of ​​territory in its attempt to become a caliphate. Responsibility for the attacks in Paris on 13 November in which 130 people were killed won.

Comey said the group has perfected the use of social networks and Twitter in particular, contact with potential supporters in the United States and elsewhere.

“Twitter works as a way to sell books, as a way to promote the film, and functions as a form of crowdsourcing terrorism – to sell murder,” Comey said.

Islamic State also uses encrypted “end-to-end” in communication with people who are believed to be willing to carry out assassinations on their behalf, Comey said.

That has been a major challenge for researchers, who often find themselves hampered even when they have warrants that give them access to the devices.

But Comey said he is convinced that companies in law enforcement and technology can work together to resolve this problem without compromising personal privacy.

“We will not break the Internet,” he said. “We will not endanger the safety of persons.”