In January 2011, the Philadelphia medical examiner performed an autopsy on Ellen Greenberg and ruled her death a homicide. Ten weeks later, after a meeting with police and a prosecutor, he changed it to suicide. No new physical evidence was introduced. A retired police commander and an active 911 dispatcher break down the 911 call, the scene, and the institutional process that changed everything. This is Part 1 of 3.

We asked people who have followed this case for years what three questions they most needed answered. The same ones kept coming back. Today we answer every one of them — starting with the phone call that put this entire investigation in motion.

Jon is an active 911 dispatcher and certified crisis negotiator. Drew is a retired police commander with 29 years in law enforcement, including criminal investigations, command administration, and 911 center oversight. Neither is an attorney.