to find (after searching everywhere); to locate; to discover
刑事は犯人を捜し当てた。
The detective located the culprit.
彼女は昔の友人を捜し当てて再会した。
She found her old friend and reunited with them.
宝探し隊は伝説の財宝を必ず捜し当てる。
The treasure hunt team will surely locate the legendary treasure.