falsely accused of assault, need ER records

A person was falsely convicted of aggravated assault on a policeman. No medical evidence was given at trial. There's reason to believe the officer was treated for a chronic health problem at the ER rather than an injury. Attorney didn't ask for discovery, so we still don't know if there was an injury. Can we get the ER records? Is it too late to ask for discovery from the DA? Who can we contact about the cop's false testimony?