. >> reporter: david quintavalle was not in d.c.ut that didn't stop self-appointed social media detectives from publicly naming him as the prime suspect. he's even received threatening calls. >> you're a ( bleep ) murderer and a traitor, and i can't believe you killed a cop. >> this needs to stop. you can't just ruin a person's career and life by making accusations that are fraudulent and untrue. >> reporter: quintavalle is a retired chicago firefighter. he says he was targeted in part because the man in the video is seen wearing a c.f.d. hat. sanford, the man actually accused of throwing the fire extinguisher, is a former member of the chester, pennsylvania, fire department. >> i'm not the guy. i did 30-some years of public service to help people, and this is not me. >> reporter: a police car now sits in front of quintavalle's home after he was wrongly accused. his address, phone number, and information about his family was widely shared on social media. david goldenberg is the head of the midwest chapter of the anti-defamation lea