In a news conference Friday (May 27), Steven McCraw, director of the Texas Department of Public Safety, revealed a more detailed timeline of events during the mass shooting on Tuesday (May 24) that killed at least 19 students and two teachers at Robb Elementary School in Uvalde, Texas.

In the updated sequence of events, there is an hour-long gap where police entered the school but did not approach the gunman. McCraw also revised facts about the shooting previously stated by other officials including the several 911 calls that were made by students to the moment the students were taken outside of the school. Below is the timeline McCraw laid out

11:27 a.m. According to video evidence, McCraw said, the door where the gunman Salvador Ramos entered at Robb Elementary School was propped open by a teacher.

11:28 Gunman crashes his grandmother’s truck into a ditch near the school. The teacher runs into the school, apparently to grab a cellphone. The gunman opens fire on two men at a funeral home across the street but misses. The teacher appears on video inside the school, now talking on a phone and believed to be calling 911.

11:30 A witness who called 911, possibly the teacher, says a car has crashed and there’s a man with a gun.

11:31 The gunman begins shooting at the school from the parking lot. Police arrive at the funeral home. A cop car drives into the school parking lot but doesn’t see the gunman, who is hiding between cars.

11:32 More shots are fired at the school.

11:33 The gunman enters the school through the propped-open door and walks down a hallway toward classrooms 111 and 112, which are connected by a bathroom. He fires more than 100 rounds.

11:35 Three Uvalde Police Department officers entered the school through the same door used by the gunman and two are grazed by gunfire. Four more officers, including a county deputy sheriff entered the building. The doors to both of the classrooms where the gunman is located are locked at this time.

11:37 Another 16 rounds are fired.

11:51 The police sergeant and other law enforcement officers start arriving.

12:03 p.m. At least 19 officers have gathered in the school hallway. A student calls 911 and whispers that she is in Room 112. The call lasts 1 minute and 23 seconds.

12:10 The same student calls 911 again and says that multiple people are dead.

12:13 The same student calls 911 again.

12:15 Members of the Border Patrol Tactical Unit arrive with shields.

12:16 The same student calls 911 again and says that eight to nine students are still alive.

12:19 A different student, this one in Room 111, calls, but hangs up after another student tells her to.

12:21 The gunman, believed to be at the classroom door, starts firing shots again. Officers move down the hallway. Shots are heard over a 911 call from inside.

12:36 The first student calls 911 again, saying the gunman shot the door. She is told to stay on the line and stay quiet.

12:43 and 12:47 The student on the line asks 911 to please send the police now.

12:46 The student says that she can hear the police next door.

12:50 Law enforcement officers breach a classroom door using keys they’ve obtained from a janitor. They shoot and kill the suspect. Shots are heard over the 911 call.

12:51 On the 911 call, officers can be heard moving children out of the classroom. The same kid who called is outside when the call ends.