ATLANTA -- Atlanta police said they've been experiencing a level of crime never seen before in the city and a lot of it was imported from New Orleans after Hurricane Katrina.

The crimes linked to the group include a murder outside Club 112 in Midtown in June and a murder in September outside a southwest Atlanta pool hall.

Police said the men are the worst of the worst. Investigators said when the eight men murdered, they used AK-47's and fired in public places. Atlanta Police Chief Richard Pennington admitted they were not the types of crimes they were used to seeing in Atlanta.

"I'm surprised they weren't confrontational when we arrested them because they were totally prepared -- bullet proof vests, automatic weapons -- the things we don't normally see here in Atlanta," said Pennington.

Pennington said that it was the type of crime he was used to seeing when he headed up the New Orleans Police Department.

In the past two weeks, Atlanta Police, the US Marshals and the ATF rounded up eight men and charged them with at least three murders and one aggravated assault.

Investigators said three of the men are Katrina evacuees and brought their violent crime spree to Atlanta.

"We know that some of these individuals being from New Orleans, they were quite violent," said Pennington.

"These crimes were committed by some of the worst of the worst criminals in the city of Atlanta," said Jeff Pearce with the ATF.

Police said George Redding, know as "Keon," was the most violent. He is charged in the Club 112 murder of Randy Griffin that left a parking lot riddled with bullets.

Investigators said the motives in the murders and assaults were robbery and retaliation. They also seized sixteen weapons in all, including eight assault rifles from one home -- a find most veteran officers have never seen.

"I personally have never seen that type of fire power in the hands of a single individual or group of individuals," said Lt. John Dalton with the Atlanta Police Department.

"Our residents have been asking, 'What has been driving the crime rate in Atlanta? Particularly murders?' We believe the eight individuals were in the front seat," said Pennington.

Authorities said they expect more charges to be filed against the eight men. Investigators said they could be viable suspects in at least three more Atlanta murders from this summer.

At least one other police department in metro Atlanta has a hold on some of the guys for a violent home invasion as well.