Question: I found money in my shul, and I can find out who lost it by checking the security cameras. Am I obligated to do so and return it?

Answer: According to strict halacha, you aren’t required to return it because the owner has likely already given up hope of recovering it (yeiush), in which case, the money belongs to the finder (Shulchan Aruch Choshen Mishpat 264). However, if you choose to go beyond the letter of the law and return it, that is the proper thing to do (Shulchan Aruch, Choshen Mishpat 259:5).