examiner vs investigator

examiner and investigator both are nouns.

Word	Noun	Adjective	Verb	Adverb
examiner	Yes	No	No	No
investigator	Yes	No	No	No

As nouns, investigator is a hypernym of examiner; that is, investigator is a word with a broader meaning than examiner:

examiner (noun)	investigator (noun)
an investigator who observes carefully	someone who investigates
someone who administers a test to determine your qualifications	a scientist who devotes himself to doing research
	a police officer who investigates crimes