From Longman Dictionary of Contemporary Englishtrack somebody/something ↔ down phrasal verbFINDto find someone or something that is difficult to find by searching or looking for information in several different places I finally managed to track down the book you wanted in a shop near the station. Detectives had tracked her down in California. → track→ See Verb table
Examples from the Corpus
track down• But after the bandits' escape through the chimney, the posse eventually tracked them down.• Cons: Just when the bobsled builds up steam, brakes on the track slow it down.• Fincara, surely, would have some magic way of tracking them down.• Deer tracks were everywhere down by the cutting.• Rich tracks her down during one of her many recruiting trips in July.• More ups than downs on the track, more downs than ups within the team.• Felix had tracked him down through his old address and left a note.• Finally he tracks it down - unwillingly - to the middle barrel. 