SAN FRANCISCO — The wife of a U.S. government contractor killed in a terrorist attack in Jordan sued Twitter on Wednesday claiming the company has provided material support for ISIS.

Tamara Fields, whose husband Lloyd “Carl” Fields, Jr. was killed in an attack on a police training center that left five people dead, filed suit against the company in U.S. District Court for the Northern District of California.

“Without Twitter, the explosive growth of ISIS over the last few years into the most feared terrorist group in the world would not have been possible,” wrote Fields lawyers at Bursor & Fisher.

A spokesperson for the company didn’t immediately respond to an email message.

The lawsuit claims that as of December 2014 ISIS sympathizers had an estimated 70,000 Twitter accounts with at least 79 of those accounts having “official” ties to the group. The company has faced growing criticism from politicians and military officials who claim Twitter should be doing more to prevent terrorist groups from exploiting its social network to spread propaganda, reach out to recruits, and raise funds. In April Twitter said that it had suspended about 10,000 accounts for tweeting violent threats in what The New York Times characterized as the largest single surge in suspensions in the company’s history.

In Wednesday’s lawsuit, Fields’ lawyers wrote that “while Twitter has now put in place a rule that supposedly prohibits ‘threats of violence … including threatening or promoting terrorism,’ many ISIS-themed accounts are still easily found on Twitter.com.”

According to the complaint, Fields’ husband traveled to Jordan last June to work as a government contractor for DynCorp International at the International Police Training Center, a U.S. State Department-funded facility training law enforcement recruits from across the Middle East. Mr. Fields, a former deputy sheriff in Louisiana and police advisor in Iraq and Afghanistan, was shot and killed by a former Jordanian police officer who had trained at the center. The complaint maintains that the media arm of ISIS claimed responsibility for the attack and issued a statement saying that “time will turn thousands of supporters of the caliphate on Twitter and others to wolves.”

Wednesday’s suit claims that Twitter violated the federal Anti-Terrorism Act by “knowingly or with willful blindness” supporting ISIS and providing it with material support for the preparation and carrying out of terrorist acts. The suit seeks compensatory damages which can be trebled under the law.

L. Timothy Fisher, a lawyer for Fields, didn’t immediately response to a phone message.

Contact the reporter at rtodd@alm.com.