Castro asked the FBI to investigate the Uvalde school massacre and the police response to it as controversy grew over how law enforcement officials responded to the scene.
The people of Uvalde, Texas, deserve an accurate account of what happened.
Castro, who represents parts of San Antonio, less than 90 miles from Uvalde, wrote that the American people have a complete and comprehensive account of how this tragedy occurred.
The congressperson's letter came as a top Texas law enforcement official contradicted earlier police reports, and said rifle-toting 18-year-old Salvador Ramos had not encountered an armed school police officer before he entered Robb Elementary School on Tuesday morning and began firing with an AR-15.
A tactical team from the U.S. Border Patrol entered the school and killed Ramos after waiting for an hour.
Nineteen children and two teachers were killed by Ramos.
According to multiple reports, parents tried to get law enforcement to enter the school.
Castro urged the FBI to use its maximum authority to thoroughly examine the timelines of events and the law enforcement response.