Facebook, Twitter and Google has been sued by the family members of three victims of the December 2015 shooting in San Bernardino, California, for “providing material support” to the Islamic State group to “spread extremist propaganda”. They believe that the companies allowed the terror group to flourish on social media, Reuters reported on Friday. And, hence, they held the companies responsible for the attack carried out by the group.

“For years defendants have knowingly and recklessly provided the terrorist group ISIS with accounts to use its social networks as a tool for spreading extremist propaganda, raising funds and attracting new recruits,” said the complaint filed by family members of Sierra Clayborn, Tin Nguyen and Nicholas Thalasinos. “Without defendants Twitter, Facebook and Google [YouTube], the explosive growth of ISIS over the last few years into the most feared terrorist group in the world would not have been possible.” The complaint was filed in US District Court in Los Angeles on Wednesday.

On December 3, 2015, three people opened fire at a social service agency’s holiday party in San Bernadino killing 14 people and injuring 17 others.