Police will work with federal authorities to investigate the surveillance video, which shows the gunman opening fire using a military-style assault weapon. (brian.ch/Flickr)

Earlier in the day, Wilkins, 44, walked into a local business and "indicated he was involved" in the shooting, which occurred around 12:30 a.m. at the Copper Top bar, near the University of Alabama. At least 17 people were hurt in the incident, one in "extremely critical" condition and three in critical condition.

Tuscaloosa Police Chief Steve Anderson said details given by Wilkins led authorities to believe he is the shooter. CNN reported that the bar's surveillance video showed a man entering the bar, looking around and opening fire with a military-style assault rifle.

Police remain uncertain of a motive, but are investigating several possibilities including a dispute between competing motorcycle gangs and whether or not Wilkins was on drugs. The co-owner of the store where Wilkins confessed said he discussed being "high on drugs" at the time of the shooting.

Read the full story at CNN and the Associated Press.

Reach Supervising Executive Producer Amanda Martinez here.