investigating vs investigation

investigating and investigation both are nouns.

Word	Noun	Adjective	Verb	Adverb
investigating	Yes	No	No	No
investigation	Yes	No	No	No

As nouns, investigating and investigation are synonyms defined as:

investigating and investigation: the work of inquiring into something thoroughly and systematically

investigating (noun)	investigation (noun)
the work of inquiring into something thoroughly and systematically	the work of inquiring into something thoroughly and systematically
	an inquiry into unfamiliar or questionable activities