once he entered, he just started shooting random. >> reporter: gary thompson works at the hospital. >> you heard at least eight shots, you saw blood -- >> yes. >> elevator lobby area? >> yeah, on the floor. >> reporter: police say there were multiple victims. officers going floor by floor, a methodical search for the gunman. one officer in critical condition, loaded into an ambulance, driven away with a police escort. >> and alex perez joins us from outside mercy hospital tonight in chicago. and alex, we understand police are now saying the hospital is secure? >> reporter: david, that is correct. officials say they have searched the hospital and it has been secured. you can see still a very active crime scene behind me here. the gunman is dead. three other victims, including a chicago police officer, are in critical condition, fighting for their lives. the motive here remains unclear. david? >> alex perez leading us off tonight. alex, thank you. and we're going to turn next here tonight to the horror revealed in a colorado courtroom today. the father who killed his