To investigate a matter thoroughly; to get to the heart of the matter.

To investigate a matter thoroughly; to inquire deeply into the root cause or origin of something

(idiom) when all is said and done; to get to the root of the matter; ultimately

to investigate thoroughly; to get to the roots of a problem or the source of a matter

to examine the roots and inquire at the base; to probe into the heart of a matter or investigate something thoroughly

to trace back to the source; to summarize by looking at the fundamental cause or essence of a situation; in the final analysis

To trace something back to its roots; to investigate a matter thoroughly to its very source.

to investigate a matter thoroughly; to get to the bottom of things

To investigate a matter thoroughly; to get to the root of a problem or situation.