UVALDE, Texas (AP) — A scathing Justice Department report released earlier this year into law enforcement failures during the Robb Elementary School shooting in Uvalde, Texas, includes a minute-by-minute account of missteps by police at the scene.

Heavily armed officers did not kill the 18-year-old gunman until about 77 minutes after the first officers arrived at the school. During that time, terrified students in the classrooms called 911 and parents begged officers to go in. Nineteen children and two teachers were killed in the May 24, 2022, massacre in the rural South Texas town.

An earlier investigation by Texas lawmakers also constructed a timeline of one of the deadliest school shootings in U.S. history.

Here is the Justice Department’s reconstruction of the shooting, which is similar to timelines previously offered by authorities:

11:21 a.m. — The gunman, Salvador Ramos, shoots and wounds his grandmother at their home, then sends a message to an acquaintance saying what he did and that he plans to “shoot up an elementary school.”

11:28 a.m. — The gunman crashes a vehicle he stole from his grandparents’ home into a ditch about 100 yards (90 meters) from Robb Elementary School.

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11:33 a.m. — He enters the school through a closed but unlocked door, walks to classrooms 111 and 112, and opens fire on their doors from the hallway. The two classrooms are connected by an interior door.

11:36 a.m. — The first responding officers enter the school. The gunman is by now shooting inside the two fourth-grade classrooms. Two officers who run toward the classrooms are hit with shrapnel and retreat.

11:38 a.m. — The first request to activate the Uvalde SWAT team is made over the radio.

11:39 a.m. — A city police officer makes the first official request for shields. Officers in the hallway begin treating the gunman as a barricaded subject rather than an active shooter.

11:40 a.m. to 12:21 p.m. — More officers from multiple law enforcement agencies arrive. During these 41 minutes, according to the report, “there is a great deal of confusion, miscommunication, a lack of urgency, and a lack of incident command.”

12:21 p.m. — The gunman fires four additional shots inside the classrooms. At this point, officers move into formation outside the classrooms’ doors but don’t enter. Officers then test keys on another door while searching for additional keys and breaching tools.

12:48 p.m. — Officers open the door to room 111, which was likely unlocked. A minute or more goes by before the officers enter the room and engage the shooter.

12:50 p.m. — The gunman is fatally shot by officers after he emerges from a closet while opening fire.