murder will out

murder will out AND truth will out (the truth will always be discovered and become known eventually; secrets or misdeeds will eventually be disclosed) — все тайное становится явным; сколь веревочке ни виться; сколько веревочка ни вейся (, а конец будет)

Example: They're bound to find out what you've done. Truth will out, you know. (CIDI)

Can be used to remark that someone who had been concealing the truth is now revealing it.