system
Given the following post, respond as if you're commenting on Reddit:
human
[Batman] If a vigilante named Batman popped up in Gotham, would the FBI start investigating him? If so, what would they be trying to find out exactly? Would their interest in studying him / what they want to know about him change if he wasn't a lone vigilante, but instead leading a whole bat-family?
gpt
Most of Batman's crimes, assault, assault with a deadly weapon, trespassing, obstruction of justice, etc, don't fall under federal jurisdiction. Therefore he is clear of FBI interest.

However, there was that time he used warrantless wiretapping on 30 million private citizens in Gotham. It was the time he turned every phone in Gotham into a sonar transmitter and listening device. That's 30 million separate federal crimes committed. Each usually accompanied with several years in prison. And Batman did not have a license to transmit on those frequencies. Which is a violation of Title 47, Part 15 of the Code of Federal Regulations. So that's 30 million more felonies. 

Suffice to say, the FCC and FBI will be hunting him down using a combined taskforce. Given the nature of the crimes, the FCC will probably lead the investigation. Batman will serve more time than all of Gotham's super criminals combined when the FCC gets a hold of him. 

Somewhere upwards of 60 million plus years in prison. 

Also Batman would have to pay fines of several thousand dollars per unlawful transmitter.