The material begins as shooter Aaron Alexis drives his rented blue Toyota Prius through a security checkpoint. A black and white camera shows Alexis entering Building #197 at 8:08 a.m. carrying a backpack. That backpack was later found in a fourth-floor men's bathroom.
Alexis can be seen carrying a Remington 870 shotgun as he moves through the hallways of the building.
Evidence photos also released shows etchings he made on his guns including the phrase: "End to the torment!"
Alexis is accused of shooting and killing 12 before being shot by authorities.
Savannah-Chatham Metro Police are investigating an overnight shooting in downtown Savannah.