Photo: ALLISON DINNER/AFP via Getty

Questions are swirling around the police response to Tuesday’smass shootingat Robb Elementary School in Uvalde, Texas — and the timeline of the incident is coming under close scrutiny.
While police, and witnesses, initially said that officers exchanged fire with the shooter before he entered the building, a Wednesday afternoon press conference disputed that claim, with authorities saying that they never engaged with him before hekilled 19 children and two adults.
Rep. Joaquin Castro, a Texas congressman who represents a neighboring district, wrote a letter on Thursday to the FBI Director Christopher Wray calling on the agency “to use its maximum authority to thoroughly examine the timeline of events and the law enforcement response and to produce a full, timely, and transparent report of your findings.”
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While the motive of the attack is still unknown, certain details have emerged about what happened. Here’s what we know:
May 17: The day after his 18th birthday, the shooter purchases a semi-automatic rifle at a local sporting goods store called Oasis Outback.
May 18: The gunman purchases 375 rounds of ammunition.
May 20: The gunman returns to Oasis Outback and purchases another gun.
May 24: The day of the shooting
11:15 a.m.: The gunman sends a message on Facebook declaring, “I’m going to shoot an elementary school.”
11:28 a.m.: McCraw says that the shooter drove about 2 miles to Robb Elementary in his grandmother’s truck. When he crashed the vehicle near the school, authorities say, he exited the vehicle through a passenger side. He was carrying a rifle and a backpack full of ammunition.
11:32 a.m.: By all accounts, the gunman entered the school on the west side of the campus at this time, scales a fence and enters the parking lot. Shots were fired.
During Thursday’s press conference, Escalon claimed that police did not engage with the shooter at this time, and he was just shooting “at the school.” Previous press briefings and witness statements had claimed that police had a firefight with the gunman.
11:40 a.m.: The gunman enters west side of the school through a door that may or may not have been unlocked, Texas Department of Public Safety regional director Victor Escalon said in Thursday’s press conference.
The shooter heads down a series of short hallways before entering a classroom that is connected to other classrooms. He finds one full of students. Inside, he opens fire, killing 21 people.
11:43 a.m.: Robb Elementary School posts on Facebook that the campus is on lockdown “due to gunshots in the area.” The Uvalde Police Department shares similar information on Facebook.
11:44 a.m.: Local police and the district police officer enter the school and hear gunfire. Escalon says in a press conference that they initially didn’t enter the classroom due to the gunfire. They fell back and called in backup, while others evacuated students and teachers.
In a conflicting account, Steven McCraw, director Texas Department of Public Safety, said that several law enforcement agencies — including Uvalde police — converged on the classroom, broke open the door, and exchanged fire with the shooter to “keep him pinned down at that location.”
Approximately 12:45 p.m.: Border patrol and tactical teams arrive at the scene. They enter the school and kill the shooter, who has been in the building for approximately an hour.
source: people.com