Advice please important

At my partner's apartment across the street from Ross/Kroger on Durham in the Heights we heard a shot coming from one of his upstairs neighbors apts and then a woman's blood curdling screams (almost sounded like a dog how bad it was) and then a door and our gate slamming and then.. dead silence. Called cops and heard them banging on the door but they left without telling us anything. We're thinking they left because no one answered. We and our neighbors are absolutely positive that someone was shot and someone left after. It was unmistakable. What can we do about this? What if they're still alive inside and unable to cry for help? When do we call again for a wellfare check and when are they able to forcibly enter? Someone left the apt immediate after the screams stopped so there may be a killer on the loose and also as a side note the light in their apartment was on when we left afterwards and it's the first time we've ever seen a light on in there. We fled to my apt in Midtown after the cops left but I can't in good conscious just leave this situation like that. Really trying to figure out what to do here. Advice would be much appreciated.