Nope. It cannot and POI has zero legal definition according to the courts and DOJ. None, zip, nada.
The minute a reasonable person would form the idea that this person had something to do with it, the term is “suspect”. That allows the police to further investigate. That investigation can find nothing, exonerate, or find evidence that elevates things to charges being filed.
And it is not universally used except by PIOs, the media, FBI twits, hit TV shows, and housewives. No professional uses it because there is no status where you can be a person of interest without being a suspect.
The fact that they are interested in you MEANS you are a suspect. Otherwise they would seek him as a witness or possible witness.
You don’t have a clue what you are talking about. I’ve practiced criminal law for for 30 years and have 100 jury trials under my belt. Neither POI or suspect have a “legal definition” as neither is defined by statute. They are just words or terms which have their general meaning. Neither has any bearing on how police can conduct their investigation. I still read hundreds of affidavits and police reports every year and POI is routinely used. Using the term suspect too early allows a defense attorney to use the “jumped to conclusions” argument at trial which has been quite successful at trial in the past. That’s the reason police began using the POI terminology.