A sergeant with the Dallas Police Department filed a federal lawsuit in California on Tuesday against Twitter, Facebook and Google, alleging the tech companies gave a platform to the terrorist organizations that radicalized the gunman who ambushed and killed five officers in July.

A sergeant with the Dallas Police Department filed a federal lawsuit in California on Tuesday against Twitter, Facebook and Google, alleging the tech companies gave a platform to the terrorist organizations that radicalized the gunman who ambushed and killed five officers in July.