It was, as the world has known for almost a year, a horrible, horrible tragedy. Even as the ambulances were arriving on that awful day, it looked like the work of one deeply troubled young man.

Why in the name of heaven did it take more than 11 months to confirm this?

The 48-page summary of the investigation into the massacre of 20 children and six female educators at Sandy Hook Elementary School in Newtown on Dec. 14 was made public Monday afternoon. The principal conclusion by Danbury State's Attorney Stephen J. Sedensky was that Adam Lanza acted alone.

The 20-year-old murdered his mother in her bed, then drove to the school, shot his way in and killed 26 people before taking his own life as police were arriving, the report says. But we knew all of this soon after the tragedy. Granted, investigators have to cover all the bases and coordinate the work of different agencies, but there is nothing in this report that justifies making the families, town residents and the state wait for more than 11 months.

It reflects a circle-the-wagons mentality that developed around this case, an effort to drag it out and keep records from public view. Officials are still battling over the release of the 911 calls; what is served by withholding them? How can the public judge the performance of its law enforcement officers without knowing how they responded?

For example, some have questioned whether Newtown police should have entered the building more quickly after they arrived outside the school. They waited almost six minutes, according to the timeline in the report. But the final gunshot — Mr. Lanza taking his own life — was heard a minute after police pulled up, so it is at best doubtful that racing into the building would have made any difference.

The report spends considerable time on Mr. Lanza's mental state. The young man “had significant mental health issues.” But it's not clear if this drove the shootings. The report says the “mental health professionals who saw him did not see anything that would have predicted his future behavior.”

We knew this also, minus a few details. But being reminded of this does make clear that more mental health screenings, while a welcome step, aren't the sole answer to stopping the country's epidemic of gun violence.

And it must be said that reading the reports reminds us yet again of the inspiring courage of Principal Dawn Hochsprung, her staff and her young students.

We have mourned and we won't forget, but it is long past time to close the book. Dragging this out has done no one any good. Hopefully the longer version of the report will be made available very soon, so we can review it and move on. As long as it remains under wraps, there will be more questions.

This editorial appeared Tuesday in the Hartford Courant.