Twitter refused to take down widely shared pornographic images and videos of a teenage sex trafficking victim because an investigation “didn’t find a violation” of the company’s “policies,” a scathing lawsuit alleges. The federal suit, filed Wednesday by the victim and his mother in the Northern District of California, alleges Twitter made money off the clips, which showed a 13-year-old engaged in sex acts and are a form of child sexual abuse material, or child porn, the suit states. The teen — who is now 17 and lives in Florida — is identified only as John Doe and was between...