Texas police faced angry questions Thursday over why it took an hour to neutralize the gunman who murdered 19 small children and two teachers in Uvalde, as video emerged of desperate parents begging officers to storm the school.

Facing rapid-fire questioning by journalists on the police response, Victor Escalon of the Texas Department of Public Safety (DPS) said investigators were still working to piece together exactly what happened.

The accused criminal of shooting

• The tight-knit Latino community was changed forever when Salvador Ramos, an 18-year-old with a history of being bullied, entered the school and gunned down students and teachers with an assault rifle.
• After shooting his own grandmother, Ramos crashed her vehicle near the school, Escalon said, then fired on bystanders before entering through a door that was apparently unlocked.
• Ramos's mother Adriana Reyes told that her son could be aggressive when angry but was "not a monster" -- and that she was not aware he had been buying weapons.
• Students who went to high school with Ramos said he bullied others as well as being on the receiving end of abuse.

Pressed on how Ramos was able to obtain the murder weapon, Texas Governor Greg Abbott has brushed aside calls for tougher gun laws in his state, where attachment to the right to bear arms runs deep.

President Joe Biden has called on lawmakers to take on the gun lobby and enact "common sense gun reforms".