The most recent timeline of events as of May 27, 2022 and are subject to revision if new data becomes available.
The Shooting (11:27-11:45)
About 11: 27 Gunman shoots his grandmother during an argument then used her truck to drive to Robb Elementary School, crashing the truck into a nearby ditch. Gunman then began shooting at people at a funeral home across the street who came to help.
Gunman climbed a fence onto school grounds and makes his way toward the school. He begins walking along the outside of the building shooting into classroom windows before walking inside at 11:33 via a door that was propped open by a teacher earlier in in the day. Gunman Fired 100 rounds by 11:35. Gunman barricades himself in classroom 111/112 behind heavy locked doors.
11:36-11:37 officers arrive enter hearing no gunfire but don’t know where the suspect is. They approach the door he is behind to try to get in and 2 officers are hit as shots come through the the door as they try to break in. The wounded officers back up and contain the room and call for backup.
11:38 - shot is heard
11:40- shot is heard
11:44- shot is heard.
11:45- Gunfire stops.
Barricaded gunman with potential hostages. (11:51-12:50)
11:51- Backup begins to arrive outside building. Suspect is locked in the rooms and not firing.
12:00-12:21- By noon19 officers are in the hallway containing the threat. No gunfire. Others are evacuating of students. Other officers arrive and set up a perimeter and panicking parents.
12:03-12:47 Periodic 911 calls come from inside room 112 and 111 saying there are still people alive inside.
12:21- Shots heard. Officers think the shots were at the door.
12:22- Officers begin moving in on the door to prepare for a breach but still do not have equipment needed for breach. 12:45- Tactical units are ready
12:50- They use keys to open the door and rush in killing the gunman. .
Source. https://youtu.be/cxXESwD8xco