Corrupt person's confession probed by new copper in office (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

I’M BENT (someone’s confession of being corrupt), containing (probed by) N (abbreviation for new) + CU (Cu = chemical symbol for copper, from Latin cuprum ). Incumbent as an adjective = descriptive of someone holding a particular position (for example a minister in a local church).