The footage — aired by CNN on Thursday and released by the Associated Press on Friday — was captured on Sept. 21, the first day of the mall siege. In the first clip, shoppers appear to see the gunmen for the first time. One man hides behind a display elephant before being spotted and shot.
In other clips, the gunmen are seen wandering in and around the four-story mall, appearing to move hostages around and look for more hostages to take.
Investigators are still trying to determine the identities of those responsible and how exactly they planned and carried out the attack.
The closed-circuit television footage has already helped confirm the identify of one of several terrorists believed to have been involved. Hassan Abdi Dhuhulow, a 23-year-old Somali-Norwegian man, was recognized from his "gait and his hand gestures" by his former classmates, according to The New York Times.
"I remember him as fanatical when it came to Islam," one former classmate told the Norwegian newspaper Ostlandsposten. "I remember him reading a lot of Web sites about Allah and about his religion."