Your own link answers the question.
The first on the scene were nine Newtown officers, divided into three teams of three, including the police chief. They were the first, after the shooter, to force their way into the school, via the front lobby and the rear door.
POLICE OFFICERS
Who ARE NOT EQUIPPED to save the lives of the dying.
If the police officers were the only ones in the building then they were reckless and may have caused additonal deaths.
It is not possible for non-EMS trained personnel to tell the dead from wounded. Police officers can not do that.
Example:
http://www.kentucky.com/2010/11/05/1510121/lexington-police-acknowledge-failure.html
If the police decided all the wounded were dead - regardless of the wounds - then there should a line of lawyers ready to sue the Newtown Police.