What is the ruling regarding the claim of a telecommunications shop owner that he did not find a wallet, which he had in fact found, and then regretted his action, and what is the expiation for that?

The man erred by claiming he did not find the wallet. His duty was to verify the truthfulness of the claimant. If he doubted, he should have shown him the wallet and delayed its handover. If the claimant's truthfulness became clear, he should have given it to him; otherwise, he should have searched for its real owner. Since what happened has happened, he must now search for the one who claimed the wallet to ascertain his truthfulness. Otherwise, he should search for its owner for a year by announcing it in gathering places and on the streets. If he does not find the owner after a year, he is permitted to donate it on the owner's behalf or use it, with the obligation to return it to its owner if he appears.