in-, into, to make, -culp, offence, fault, 語源的にはculprit, exculpateと同じ。
英語の語源
inculpate (v.)
1799, "to accuse, bring charges against," from Medieval Latin inculpatus, past participle of inculpare "to reproach, blame, censure," from Latin in- "in" (see in- (2)) + culpare "to blame," from culpa "fault." But inculpable (late 15c.) means "not culpable, free from blame," from Latin in- "not" (see in- (1)) + culpare.