BBM: From the way this is worded, this was apparently written by a media outlet.. not by a LE official. Makes a big difference, IMO.
The media can say anything they want to, and word it so that they don't cross any legal lines. But saying that someone is a suspect or a POI when it has not been confirmed by LE publicly can get them in deep trouble.
Technically, the two terms may mean the same thing to a lot of people, but in reality, a person of interest can also mean someone who LE believes has knowledge of a crime, or was an accessory to a crime, according to my son who is in LE. 'POI' is a kind of broad term, meaning LE may think this person could be responsible, whereas 'Suspect' is more narrowed down, meaning they believe the person is responsible but don't quite have enough to make an arrest.
Does that make sense?
The portion of the article that I found pertinent was:
But in some major cases, such as this one, the information our reporters gather makes it clear to us that a “person of interest” is indeed a suspect and authorities are preparing to seek charges, even if those charges haven’t yet been filed.
I simply included the lines before, and after, for clarity. I wasn't trying to make any statement about the media, one way or the other. Reading my post again, I see where you are coming from, in thinking otherwise.
My point was that LE doesn't name a POI until they see fit - and, the reasons for that are many (what do they have to gain by naming a suspect/POI? What information can be garnered by releasing that information? How will it effect the investigation, etc.?).
Further, once LE names a suspect/POI, and thus limits the scope of the investigation to zero in on that individual - whether in an actual, suspect sense, or a more peripheral fashion, as a person of interest - it narrows the other avenues available to them, such as, putting out information in the media, interviewing people who do NOT know they have a current suspect in their sights, etc.
It's extremely rare, although NOT entirely unheard of, to declare a POI....and then NOT file charges within a short time frame. Generally, that's how it goes: The announcement of suspect/POI status is made, and POOF! Indictment soon to follow. That's the usual fashion in which it occurs.
I can recall only a handful of investigations that sputtered out, after declaring a POI, and charges were never filed. Sometimes, the media pronouncement of a POI is the final hurrah - a way of trying to obtain that elusive final puzzle piece.
ETA: Regarding suspect/POI...it's practically commonplace, at least here in Chicago, to state "POI" in lieu of "suspect" as a form of avoiding liability - there have been a slew of cases where former 'suspects' have sued for defamation, but that's really neither here nor there. I agree, a POI is not mutually exclusive with suspect by definition, but, in practice? It kinda is. See the link below for an excellent article regarding the reasoning behind labeling as a POI vs. suspect....
http://www.ajr.org/article.asp?id=4042