Generally, are police and DA departments very territorial?

Factual Questions
1

Inspired by a Law & Order episode, but I’ve seen this recurring theme in other works as well

A suspect has committed a serious crime (let’s say murder) in District A, but he’s also being physically kept in District B for a less severe but still serious crime (let’s say kidnapping). The DA of District A usually frames it like “How would you answer to the people in District A where a murderer is being kept from justice?” and District B usually responds with “He committed a serious crime here too, we want to bring him to justice in District B”

In real life, I would imagine there are procedures to settle this, especially if one is a federal crime and one is a state crime. But on TV, the implication often is that if a guy gets a lesser charge in District B, that somehow absolves him from facing a court in District A. How accurate is TV in this premise? Would real life DA’s really worry about their districts only to the detriment of another, even if the suspect can get a harsher sentence if District B gives him up to District A? And why wouldn’t they simply try him at both locations one after the other?

Let’s throw some extra drama into this by injecting the fact that District B has proof of the suspect’s guilt of murder in District A, but that proof somehow makes the suspect less likely to get convicted in District B. Would the DA in District B really withhold that evidence in real life? Where does it matter where the guy is jailed as long as he’s jailed?

2

being held, charged, tried and convicted in one state does not get you off the hook in other states for other crimes. It just means they may have to wait until the case is finished before they can extradite from State A to State B, since the accused must be present for a trial (unelss there’s a really good reason, IANAL).

Some cases can take years, so it’s obvious that many prosecutors don’t want to wait. A lot can happen in two or 3 years - witnesses die, forget, get discredited, or go missing, evidence is lost, etc. the sooner the better. There’s no great headline in prosecuting someone when the trial is 4 or 5 years later. (Casey Anthoney, for example, spent 3 years in jail before she was found not guilty.)

If a prosecutor has any evidence that affects the case, good or bad, he must pass it to the defence. he cannot spring it in trial. In fact, usually in L&O when the police find some new detail, the prosecutors questions are more like “When did you find this? Why didn’t I know sooner? How long have you had this? I have to tell the defense lawyer right away!” If there’s any hint the prosecution, or the police, were hiding details to protect their case or persuade the defendant to plead guilty - case may go to retrial or more likely, case dismissed.

Prosecutor Nifong was disbarred for attempting to hide the detail that the “victim” in the Duke Lacrosse “rape” case had DNA of several males from the rape kit swab, none the Duke accused. His argument was that it was irrelevant. Now his career is.

If a woman accuses you of gang rape, and DNA says some guys but not you did have sex with her, how could that not be at least somewhat exonerating evidence?

From teh Wikipedia article it looks like the police and prosecutor had it in for Duke students; in the end, playing fast and loose with the evidence and facts cost the city (according to the link) possibly tens of millions of dollars. The moral is, you don’t want to fudge the system while working as a prosecutor, and especially, you don’t want to try and railroad people whose parents can afford fancy expensive lawyers.

3

Different crime, different jurisdictions, if District B doesn’t want to hand him over, they try, convict, jail him, etc. At the end of the jail term, then District A’s warrant for arrest is now applicable and they hand him over to District A which tries, convicts, etc. The big headache for District A is that if enough time passes, they are going to have a harder time rounding up witnesses and such. District B also might allow District A to take the guy after their trial part is done and then they work out who jails the guy where for how long.

But usually the District that’s charging the more serious crime gets the guy. The other District will prefer that Someone Else pay for a big trial and keeping the perp behind bars as long as possible.

Same crime, different jurisdictions. State and Federal prosecutions don’t cause double jeopardy issues, so the above more or less applies. But if it’s local, e.g., state and county, then all sorts of games can take place. Sometimes, quite unethical. A prominent local might get into rush things thru a friendly village court, plead guilty to a lesser crime (disturbing the peace) and that blocks prosecution by the state or county for the real crime (trying to kill someone).

4

The Perfect Master speaks: Who’s the boss, city cops, state cops, or the Feds? - The Straight Dope