July 20: 12:05am Batman — The Dark Knight Rises — starts
Federal law enforcement sources: Holmes slipped out of the theater once it began and propped open the emergency exit before gathering his weapons and gear and coming back into the theater
12:10am: Witnesses told The [Denver] Post the suspect entered through an emergency exit at the right front of the Theater 9 less than 10 minutes into the film.
About 10 minutes later — 20 minutes into the film — the suspect appeared at the front of the theater with his weapons and gas mask
He then threw a canister that released some kind of gas, after which a hissing sound ensued
about 12:20am to 12:30 a.m [MDT -- about 2:30am EDT] moviegoers start smelling smoke
One shot was first fired into the air
Shots were fired for some 15 to 20 minutes after they first started [according to witnesses]
Shots were not fired in rapid succession
Around 12:39 a.m., police received several reports of the shooting at the Century 16 Movie Theaters at the Aurora Town Center
12:46am: Police find rifles, gas mask in car parked behind the theater
12:49am: Aurora police request help from Denver police
12:50am: Police have conflicting reports on suspects. Witness reports lead police to believe there is another suspect at this time.
12:53am: Police clear theater
2:00am: Apt complex where Holmes lives is evacuated by Aurora police
[source: Witness accounts // wires // Denver Post]