investigator vs police detective

investigator and police detective both are nouns.

Word	Noun	Adjective	Verb	Adverb
investigator	Yes	No	No	No
police detective	Yes	No	No	No

As nouns, investigator and police detective are synonyms defined as:

investigator and police detective: a police officer who investigates crimes

Other synonyms of investigator include detective, tec.

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