​F​amilies of the Orlando nightclub shooting ​victims ​have filed a highly unusual federal lawsuit ​blaming Twitter, Google and Facebook for promoting​ –​​ and even helping fund –​ terrorism.

ISIS-inspired gunman Omar Mateen, killed 49 people and wounded 53 others at the Pulse night in June before ​teh 29-year-old was​ gunned downby a SWAT team, ending what is the country’s deadliest mass shooting.

“ISIS’ use of social media directly influenced [Mateen’s] actions on the night of the Orlando massacre,” the Michigan federal suit says.

FBI Director James Comey said he’s “highly confident that this killer was radicalized at least in part through the Internet.” Mateen viewed jihadist speeches online, downloaded videos of beheadings and searched Facebook for posts relating to the California couple who killed 14 people at a holiday party last December, the suit says.

Without Twitter, Facebook and Google, “ISIS would not have been able to radicalize Omar Mateen leading ​to the deadly attack in Orlando,” the suit says.

The terrorist organization has recruited 30,000 followers through the sites since 2013, the ​filing states.

Family members of ​Pulse ​victims Tevin Eugene Crosby, Juan Ramon Jr, and Javier Jorge-Reyes filed the case saying the social media companies violate an anti-terro​​rism law by providing “material support” to ISIS.

The terrorist organization raises money through Twitter and Facebook while Google even shares add revenue with ISIS, the suit says.

The Michigan case is at least the second s​uch suit against Twitter. The first, related to a “lone wolf” terrorist who murdered two Americans in Jordan, was tossed ​out ​by a California judge who cited the 1996 Communications Decency Act.

That law absolves sites like Twitter of liability for content posted by third parties.

Attorney Andrew B. Lustigman, a technology legal expert who is not involved with the case, said the relevant section of the act “is going to be a barrier.”

“From a legal standpoint I would say that I think the plaintiffs have a very difficult case ahead of themselves primarily because of the Communications Decency Act, which basically is designed to immunize companies like Facebook, Twitter and Google for basically publishing other peoples messages,” Lustigam said.

“If they were involved in the creation of messages it would be a different story,” he said.

A spokeswoman for Facebook said that there is “no place on Facebook for groups that engage in terrorist activity.”

“We sympathize with the victims and their families,” the spokeswoman said.

Google did not immediately respond to a request for comment.