olemus
sõltub kontekstist, sageli tähendab kahtlusalust;
DoD kontekstis: isik, kelle kohta on teabevajadusi või teabe leidmise eesmärke

Wiktionary:
(law enforcement) someone who police have reason to believe may have a connection to a crime, or to possess important information relating to that crime, but who has not been accused or charged by authorities nor been officially deemed to be a suspect
This is an informal, nonspecific term, typically used precisely in order to avoid publicly labeling someone as a suspect without sufficient evidence.

ülevaateid
https://www.bobbybarinalaw.com/blog/2019/december/understanding-the-difference-between-a-suspect-p/

https://en.wikipedia.org/wiki/Person_of_interest