It’s a staple of investigations and reporting that eyewitness accounts are always (or at least often) the least reliable way to ascertain facts about an incident (any incident). I suspect this follows that pattern. People in a situation like that are often and understandably very upset and filled with adrenaline and subject to getting things very, very wrong. Physical evidence is FAR more reliable.
Maybe physical evidence at autopsy will reveal if different guns killed people. Did any police bullets hit anybody?