a scientist who makes (especially chemical) analysis

person who examines and determines; psychoanalyst

a person who assesses property, income taxes etc

examiner

a person who inquires

questioner

an official who inspects, e.g. schools, factories; an official who examines (manufactured articles, tickets etc)

examiner

a person who tries to set secret information, especially about military affairs of other countries; a person who keeps a secret watch on the movements of others

person who secretly finds out about another's business