The head of Philadelphia's FBI field office is facing an investigation after she shot and killed a pit bull outside a Center City apartment building Monday evening. The shooting of a pit bull by an off-duty FBI agent on a busy Center City street this week has sparked an uproar on social media and protests by animal rights activists outside the FBI’s offices on Arch Street. Here’s what we know about the incident, the agent involved, and what happens next: What do we know about the incident? Philadelphia police and the FBI have confirmed that an off-duty FBI agent shot...