Families who lost loved ones in the 2022 attack on an elementary school in Uvalde, Texas, have sought for nearly four years to hold accountable the police who waited more than an hour to confront the shooter while children and teachers lay dead or wounded in classrooms.

Now one of the first officers on the scene is about to stand trial on multiple charges of child abandonment and endangerment. Former Uvalde schools police officer Adrian Gonzales is accused of ignoring his training in a crisis with deadly consequences. His attorney insists he was focused on helping children escape from the building.

The trial that starts Monday offers potentially one of the last chances to see police answer for the long delay. The families have pinned their hopes on the jury after their gun-control efforts were rejected by lawmakers, and their lawsuits remain unresolved. A few parents ran for political office to seek change, with mixed results.

The proceedings will provide a rare example of an officer being criminally charged with not doing more to stop a crime and protect lives.

Jesse Rizo’s niece was one of 19 children and two teachers killed by the teenage gunman in one of the deadliest school shootings in U.S. history. Nine-year-old Jackie Cazares still had a pulse when rescuers finally reached her, Rizo said.

“It really bothers us a lot that maybe she could have lived,” he said.

Only two of the 376 officers from local, state and federal agencies on the scene have been charged, haunting the families, including Velma Lisa Duran, whose sister, Irma Garcia, was one of the teachers gunned down. “What about the other 374?” Duran asked. “They all waited and allowed children and teachers to die.”

Prosecutors will likely face a high bar in winning convictions, as juries are often reluctant to find law enforcement guilty of inaction. The indictment against Gonzales suggests he placed children in imminent danger by failing to act during the shooting.

The trial has been moved to Corpus Christi for impartiality. As the community continues to bear the scars of that tragic day, the families of the victims continue to seek justice on various fronts, including legal avenues and advocacy for policy changes.