I apologize; I misunderstood the intent. I thought you were looking for more articles and couldn’t locate any.
And I agree; I thought the FBI were the ones that go after bad guys in general, especially when it involved multiple jurisdictions or crimes beyond the scope of the local law enforcement to handle (e.g. serial killers).
But when I googled FBI to find their website, the first thing that was listed was this: Submit a tip-The public can report violations of U.S. federal law or suspected terrorism or criminal activity to the FBI online or via telephone or mail.
Second was: US. Capitol Violence-FBI Seeking Information Related to Violent Activity at the U.S Capitol Building. Thank you for your interest in submitting digital media tips to the FBI regarding ...
FINALLY we get to: The FBI is a federal investigative and intelligence agency with jurisdiction in a wide range of federal crimes; national security matters such as terrorism and espionage; cyber/computer crimes and intrusions; and intelligence activities that relate to those missions.
“...I thought the FBI were the ones that go after bad guys in general...”
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You can also go here (these are the guys that actually prosecute)
Example:
https://www.justice.gov/opa/pr/man-convicted-receiving-soliciting-and-promoting-child-pornography

Many questions are raised by the revelation of the ‘Nigerian Connection’.
Among those are: