The Ruling on Lost Property If It Is Not Identified

Question : I found a sum of riyals, took it, and spent it. What is required of me now?

Answer: It is obligatory for you to announce it. If you announced it for a full year, two or three times every month, saying, “Who has the lost dirhams in such-and-such a place?” in gatherings of people, around the doors of mosques, or in the markets, and a year has passed since your announcement, then it is lawful for you. If its owner comes and identifies it by its specific characteristics, you give it to him, because it is with you like a deposit. So if he comes, you give it to him.
As for if you did not announce it, but ate it and remained silent, you must give it in charity in the causes of righteousness, intending it on behalf of its owner, because you did not fulfill the conditions for its permissibility, which is announcing it. And its reward will reach him, by the permission of Allah (Glorified and Exalted is He), and success is from Allah.