chase down
verb1
to pursue and apprehend someone or something.
- With Carlos Tevez chasing down every lost cause like his life depended on it, City always had an out ball but Arsenal had such a monopoly on possession that they barely had to give thought even to the Argentine.2011 January 5, Jonathan Stevenson, “Arsenal 0 - 0 Man City”, in BBC:
2
Broadly to investigate the cause of something