The headline-writer is very up-to-date: He/she must have thought: “Hmm, the lead says ‘almost tagged a suspect’; but we cannot use ‘near-suspect’, or ‘almost suspect’, or ‘ex-future suspect’…”
“Person of interest” is what U.S. police officers use to refer to those who are/ were included in the investigation but not officially considered a suspect; and it’s what American news agencies also use, quoting law-enforcement agencies, to protect themselves from any suit (the word “suspect” has derogatory connotation.) The term has found itself in certain U.S. criminal statutes: “Person in interest shall mean the person who is the primary subject of a criminal justice record”.
Although… I think this is still journalese or legalese or policelese/ coplese, so some journalists put it in quotes, in the same way as “LPA” or “low pressure area” is weatherlese… Now, how to translate that to Filipino… “taong may interes”? “taong pinag-iinteresan”, “taong kamuntik nang pagsuspetsahan”, “taong pwede pang pagsuspetsahan”?… take your pick.