Newtown shooting report to focus on 911 calls

STAMFORD, Conn. -- It's been almost a year since the shooting at Sandy Hook Elementary School in Newtown, Conn. Twenty children and six adults were killed.

On Monday, the state attorney will release a report on what happened that day.

Complete Coverage: Newtown shooting

In the 11 months since the Newtown tragedy, Connecticut's state attorney has investigated every second of what happened that day. One area of focus is police response - whether procedures were followed, and if they were effective.

Dispatch recordings show the first 911 call came in just before 9:36. The first officer arrived a minute and a half later. The tapes indicate officers were inside the school by 9:44. 

Through interviews with officers and by examining tape recordings of the body microphones many were wearing, the report is expected to give a clear timeline of events but not necessarily make recommendations.

CBS News correspondent Don Dahler asked Conn. Sen. Richard Blumenthal what new information he expected the report to reveal.

"I think, primarily, this report will be a very factual, straightforward recitation of facts that may be known already but in their overall impact, I think will not only revive but to some extent reveal the immensity and monstrosity of this tragedy again and I hope create some additional momentum for gun violence prevention," Blumenthal said.

In the past year, many school districts nationwide have beefed up security, but efforts to establish background checks for firearm purchases that could limit access for the mentally ill have gone nowhere.

"I think that school security has to be improved. That will be a lesson of the report, and of course longer term mental health initiatives," Blumenthal said. "What could have been done to reach Adam Lanza before he committed this horrific act?"

Nicole Hockley, the mother of victim Dylan Hockley, told CBS Evening News anchor Scott Pelley one thing will never be known.

"I would love to know why-- but I think that's a question that is never going to be answered - and I don't expect that to be in the police report - we'll never know what went on in that shooter's mind," she said.

The report will be released online Monday afternoon.