After the dust settled after America’s latest school shooting, members of both political parties have been left stunned by the police response to the tragedy.

A Texas Democrat has asked the FBI to launch a comprehensive investigation into the police response to Tuesday’s shooting massacre at an elementary school in Uvalde, Texas.

Rep. Joaquin Castro (D-Texas), who represents San Antonio, roughly 80 miles east of Uvalde, said the conflicting accounts from state officials, including inconsistent depictions of law enforcement actions, are adding insult to injury for the victims’ families. 

In a letter sent Thursday to FBI Director Christopher Wray, Castro asked the agency to clear up the discrepancies with an independent probe of its own.

“I urge the FBI 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 on your findings,” Castro wrote. “Your agency must ensure that the American people have a complete and comprehensive account of how this tragedy occurred.”

Law enforcement officials have come under growing scrutiny for their actions during the massacre at Robb Elementary School in Uvalde, where a lone gunman barricaded himself on Tuesday, killing 19 fourth graders and two teachers with an AR-style rifle. After a standoff of more than an hour, a special unit of Border Patrol officers confronted the 18-year-old gunman inside the school, shooting him dead.

Video has emerged showing a crowd gathered outside the school while the gunman was still alive, urging heavily armed police officers to rush into the building to confront him. With their calls ignored, some offered to go in themselves. As the days have passed, a growing number of the victims’ family members are irate that the officers did not engage the gunman more quickly. 

State officials have added to the confusion surrounding Tuesday’s events, delivering information that’s conflicted with eyewitness accounts or turned out to be simply wrong. 

On Wednesday, for instance, state officials said a school law enforcement officer had confronted the gunman outside the building but could not prevent him from going in. A day later, another official said there was no such encounter.

“He walked unobstructed initially,” Victor Escalon, a regional director of the Texas Department of Public Safety, told reporters on Thursday. “He was not confronted by anybody.”

In his letter to Wray, Castro pointed specifically to those missteps, while expressing frustration with the long passage of time before the gunman was confronted inside the school. 

“[A] block of time between 11:30 a.m. and 1 p.m. local time has yet to be fully accounted for,” he wrote. “Onlookers allege that parents unsuccessfully urged law enforcement to enter the building during this time and confront the shooter.”

State officials have already launched a formal investigation into the police response, which is being led by the Texas Rangers. The FBI is helping the Rangers analyze surveillance footage surrounding the shooting, The New York Times reported. But Castro wants the federal agency to take the reins of the probe. 

“The people of Uvalde, of Texas, and of the nation deserve an accurate account of what transpired,” Castro wrote to Wray.