A long-awaited report on law enforcement response to the 2012 school massacre in Newtown, CT, concludes state police handled the response effectively, but it recommends improvements to protecting crime scene integrity, dealing with victims' families and other issues, reports the Associated Press. A 2013 report on the response by Newtown police said that department responded rapidly and followed policy.

After the massacre, police officials not involved in the investigation and "dignitaries" were allowed into the building and potentially contaminated the crime scene by stepping on bullet casings and glass shards that had yet to be processed as evidence, according to the report state police released Friday on their response to the mass shooting.

Gunman Adam Lanza killed his mother at their Newtown home before shooting his way into Sandy Hook Elementary School on Dec. 14, 2012, and killing 20 first-graders, six educators and himself. Investigators never found a clear motive but said Lanza suffered mental health problems and was obsessed with mass shootings.

"The unprecedented nature of this incident posed numerous challenges," the state police report says. "The unique dynamics of this tragedy tasked the agency's resources and tested the capacity and capabilities of individuals and units alike. ... Had it not been for the heroic actions of the teachers, school staff and the response force, the number of victims could have been higher."