A special Texas House investigative committee probing the Uvalde school massacre found multiple failures occurred leading up to the horror and involved everyone from law enforcement to social-media platforms, a report said Sunday.

Other entities to blame included the school itself, Robb Elementary, and the shooter’s family, CNN said, noting it had an early copy of the probe’s finding.

The panel was also set to officially release surveillance footage of the school’s hallway during the May 24 attack, which left 21 people dead. The Austin American-Statesman published the surveillance footage Tuesday after it was leaked to the paper.

The report is expected to detail testimony from about 40 people who spoke to the committee, including the school’s principal, a teacher, the district superintendent, custodial staff, members of the Texas Department of Public Safety and the school district’s police chief, CNN reported. 

The findings are expected to include a complete timeline and sequence of events, details on the shooter, a law-enforcement manifest and direct quotes from those who testified, sources told the outlet.

The committee’s chairman, Republican state Rep. Dustin Burrows, promised the group would do “everything in its power” to answer questions about the massacre and provide facts about what happened “leading up to, during, and in the aftermath of this tragedy.”

Loved ones of those killed or injured in the attack were to have a chance to review the hallway surveillance video showing law enforcement’s response to the shooting before a sit-down meeting with the committee, the outlet reported. 

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Late Saturday, Uvalde and Texas officials were hand-delivered printed copies of the report out of concern it would be leaked to the press before the families had a chance to read it, officials who were given the report told the outlet. 

The move came after the American-Statesman published the surveillance footage, sparking a wave of outrage from officials and families who were upset the materials were released publicly before they had a chance to review it. 

The newspaper defended its decision in an editorial, saying the public had a right to see it. 

The report is coming nearly two months after 18-year-old gunman Salvador Ramos stormed into Robb Elementary School and shot and killed 19 kids and two teachers. 

Local law enforcement who responded to the scene has been excoriated for waiting more than an hour in a hallway of the school before taking down the gunman. 

Ramos was eventually killed by authorities. 

Additional reporting by MaryAnn Martinez