To say nothing of the bureaucratic fun that occurs when the US government is forced to work with itself in a JTTF-type situation.
1. Departments are territorial and image conscious (most being headed by elected officials or political appointees).
2. Individuals don't get promoted by passing up chances to work on those sorts of investigations. Even if they're nonsense.
If the feds want to check something out in a joint investigation situation, I can easily see 'federal agents want to have a talk' becoming 2 feds + 2 state/county + 2 local detectives.
1. Departments are territorial and image conscious (most being headed by elected officials or political appointees).
2. Individuals don't get promoted by passing up chances to work on those sorts of investigations. Even if they're nonsense.
If the feds want to check something out in a joint investigation situation, I can easily see 'federal agents want to have a talk' becoming 2 feds + 2 state/county + 2 local detectives.