chase down

chase down (third-person singular simple present chases down, present participle chasing down, simple past and past participle chased down)

1. to pursue and apprehend someone or something.
   • 2011 January 5, Jonathan Stevenson, “Arsenal 0 - 0 Man City”, in BBC‎:

     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.

2. (by extension) to investigate the cause of something