Ten Most Wanted - What do the feds do now?

From CNN on the capture of someone on the FBI’s Ten Most Wanted list:

“New Orleans FBI agent Charles Matthews told CNN the relatively minor federal charges against Caston will not be pursued now that Caston is in custody and faces state murder charges.”

This guy was wanted by the FBI on “minor” charges, yet makes their most wanted list. Then they drop their charges.

What do the feds do now? I realize they may do corporate type anti-trust, tax evasion, etc crimes.

Do they ever arrest [FBI] and prosecute [Justice Department?] people?

Do they just provide federal assistance to local cops?

Can local cops arrest someone for federal crimes? If the FBI is to arrest someone, can the local cops help [I’m sure they do, but can they legally] or do they just wait and then arrest the guy for assaulting an officer if he resists?

The newest addition to the Ten Most Wanted List is a musical pedophile (did some session work for John Mellencamp in the early '80s) wanted in the US and Thailand for Corrupting and Endagering Minors, Distribulion, and Conspriacy to Distribute, Child Pornography, and a host of associated crimes.

BTW: TTOAWAL==Threat TO Our American Way Of Life

Yes, of course the feds arrest and prosecute people. There are all kinds of federal crimes, not just white-collar stuff. Just off the top of my head, you can get in trouble with the feds for committing a crime against a federal employee or property (think Tim McVeigh) or committing a crime that crosses state lines (Ted Kazynski). For instance, kidnapping a person in New York is a state crime, but taking that person to New Jersey makes it a federal crime.

From what I gather, the FBI occasionally helps out local authorities with purely local cases, assuming the locals ask for the help. News reports often mention forensic evidence being sent to the FBI crime lab, and you also hear about FBI profilers and such helping out with serial killers. I also have a good friend in the Border Patrol, and I know that she’s arrested people who the local cops were after.

Anything to do with kiting bad checks, counterfitting and securities fraud, arson resulting in death of a firefighter, pretty much anything that involves the Post Office, transportation systems or electronic communication, graft & corruption (ala the Mayor of Camden, NJ), etc. The list in d*mn-near endless.

I’ve known a few federal officers in various agencies. It’s professional courtesy for them to inform local officials of their presence in any jurisdiction in which they are “on duty” - which means 24/7, whether there on a particular case or not. Since they are empowered to enforce federal law, it’s good sense. You don’t step on any toes, and you don’t get shot. Plus, if something unexpected comes up, the locals have a list of people they can call for assistance. (“The President … is coming here?”). I know this applies to any jurisdiction in which an officer resides, but I do not know if applies to the jurisidiction in which he or she normally works. Nor do I know if this professional courtesy is actually mandated by law somewhere.