CBS correspondent John Miller is a former assistant director of the FBI. He has been talking to his law enforcement sources about Friday's shooting at Sandy Hook Elementary School.
It's going to be very difficult for police to deal with such a large crime scene, especially because they have competing pressures.
First of all, with the crime scene, authorities only have one chance and have to get it right the first time.
They have a large number of bodies to deal with, the people who are killed on scene. They also have a large amount of ballistic evidence to preserve and document there.
But the competing pressure - which is one that's going to weigh very heavily - is these victims' families are going to want the bodies of their loved ones back. They're going to want to start to set up burial and funeral arrangements. The fact that the victims are children is going to increase that pressure.
Police are now developing a crime scene plan that is going to run through the weekend, likely 24 hours a day with crime scene experts in shifts until the scene is complete.