How the ATF and Baltimore police figured out who shot an off-duty officer and helped stop a deadly crime spree

With the push of a button, the door to Baltimore Police Sgt. Isaac “Ike” Carrington’s van opens up, and a ramp deploys onto the asphalt. He guides his wheelchair up and inside, positioning himself where the driver’s seat would normally be. A handheld device allows him to navigate the vehicle. Sometimes he runs errands. Other times he’ll visit the Fraternal Order of Police lodge in Hampden. But when he travels to his home in Northeast Baltimore, he can only sit in the driveway and visit.