U.S. Court of Appeals for the Ninth Circuit. Photo: Jason Doiy/ALM

A federal appeals court in California ruled Wednesday that the families of two defense contractors killed in a 2015 terrorist attack in Jordan cannot sue Twitter for allegedly enabling terror group ISIS.

A three-judge panel of the U.S. Court of Appeals for the Ninth Circuit affirmed a ruling by U.S. District Judge William Orrick of the Northern District of California, who said Twitter was not complicit in the Nov. 9, 2015, shooting deaths of the contractors, Lloyd Fields Jr. and Damon Creach.

Ninth Circuit Judge Milan Smith, joined by fellow Circuit Judge Sandra Ikuta and U.S. District Judge Steven McAuliffe of the District of New Hampshire, sitting by designation, affirmed a decision by Orrick, sitting in San Francisco, to dismiss the case.

Smith said the panel agreed with Orrick that the families were unable to demonstrate that Twitter knowingly cooperated with ISIS, which through its accounts discussed and bragged about the deaths of Fields and Creach.

“Proximate causation was not shown in this case,” Smith said. “Though we do no diminish the tragedy of the events that led to this lawsuit, we hold that [plaintiffs] have not pleaded that Twitter's provision of accounts and messaging services to ISIS had any direct relation to the injuries … suffered.”

Both Fields and Creach were from Florida. Twitter is headquartered in San Francisco.

According to the court, Creach worked as a law enforcement instructor for DECO Inc., a privately held company that performs a range of law enforcement and security work, and Fields, who also was an instructor, was employed by DynCorp International, another contractor.

Three others died and six others were wounded in the attack at the Jordanian International Police Training Center in Amman. A Jordanian police captain, Anwar Abu Zaid, was the lone gunman, and ISIS reportedly claimed it was responsible for the attack. Abu Zaid was shot and killed by Jordanian security officers, press reports said at the time.

Fields' and Creach's families sought damages from Twitter under the federal Anti-Terrorism Act. Both Orrick and the Ninth Circuit said the families were unable to demonstrate any causal relationship between the shootings and ISIS's statements on Twitter, and any complicity on Twitter's part.

“Communication services and equipment are highly interconnected in modern economic and social life, such that the provision of these services and equipment could be expected to cause ripples to flow far beyond the defendant's misconduct,” Smith said.

“Nothing … indicates that Congress intended to provide a remedy to any person reached by these ripples,” Smith added. “Moreover, we are troubled by the seemingly boundless litigation risk that would be posed by extending ATA's bounds as far as foreseeability may reach.”

The attorney for the families, Joshua Arisohn, said in a statement that an appeal of the ruling is being considered.

“Here, Twitter knowingly provided social media accounts to ISIS and ISIS used those accounts to recruit thousands of new members,” said Arisohn, of the New York office of Bursor & Fisher.

ISIS, Arisohn said, used its Twitter accounts to “amass the resources” needed to carry out the attack that led to the deaths of Fields and Creach.

“Requiring a more direct connection between the provision of material support to terrorists and the attacks they carry out contravenes the central purpose of the Anti-Terrorism Act: holding enablers of terrorists accountable,” Arisohn said.

Twitter retained former U.S. Solicitor General Seth Waxman, now with the Washington office of Wilmer Cutler Pickering Hale and Dorr. He did not return a call seeking comment.