A Royal Mail investigator hired to solve thefts in by his colleagues instead pocketed cash and valuables from parcels.
Stephen Matthews, 39, helped himself to special delivery bags containing goods worth almost £2,000 which should have been evidence in his own inquiries.
Wedding rings, passports and airline tickets ended up stashed under his desk instead of being delivered to the people they were posted to.
Matthews, who claims he committed the crimes because he ran up an £80,000 debt on credit cards, could be jailed when he is sentenced at Lewes Crown Court.
Fellow investigators caught him in the act when they searched his desk at the North Road sorting office in Brighton and found 35 special delivery and recorded delivery postal packets.
Staff had became suspicious when Matthews confided to them that he was heavily in debt.
Matthews, of Greenacres, Shoreham, admitted theft and fraud at Brighton Magistrates' Court today.