investigator vs researcher

investigator and researcher both are nouns.

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

As nouns, investigator and researcher are synonyms defined as:

investigator and researcher: a scientist who devotes himself to doing research

Other synonyms of investigator include research worker.

investigator (noun)	researcher (noun)
someone who investigates	a scientist who devotes himself to doing research
a scientist who devotes himself to doing research
a police officer who investigates crimes