finder of lost property
Legal and formal term for a person who finds and takes custody of lost items. Often used in contexts related to the Lost Property Act.
The finder of lost property must promptly report the lost item to the police.
Common word for a lost item; 拾得者 is a formal, legal term for the finder.
Compound of 拾得 (しゅうとく, 'finding and taking custody') + 者 (しゃ, 'person'). The term is primarily used in legal contexts.