WACO, Texas - There are reports gang members involved in Sunday's shooting at the Twin Peaks restaurant in Waco, Texas, may return to the area, but police say they are prepared, reports CBS News correspondent Vicente Arenas.

More than 200 bikers from at least five outlaw motorcycle gangs gathered at the restaurant for what was part motorcycle recruiting event, part turf war. They are some of the world's most notoriously dangerous, including the Bandidos, Cossacks and Scimitars.

Police were prepared for possible criminal activity and responded within seconds.

Investigators have been combing through the parking lot of Twin Peaks, where at least nine riders were killed.

"This scene is probably one of the most horrific scenes I've seen in my 34 years of law enforcement," Waco police Sgt. W. Patrick Swanton said.

Police say the rumble erupted over a parking issue, starting with fists and feet inside and quickly escalating to the parking lot with chains, clubs, knives and firearms. SWAT teams fired back ending the brawl within seconds.

"I crawled back towards the freezers with a lot of the waitresses and some other people. It was really, really scary," one witness said. "We didn't know if somebody was going to come back.".

At least 100 bikers were detained and on surrounding freeways, police pursued other riders for questioning.

Swanton said Waco police have been aware of criminal biker gangs gathering at the city's Twin Peaks for months.

"We have attempted to work with the local management of Twin Peaks to get that cut back, but to no avail," Swanton said. "Apparently the management wanted them here, so we didn't have any say so on whether they could be here or not."

On Facebook, an operating partner for the Twin Peaks Waco franchise wrote, "Our management team has had ongoing and positive communications with the police"

Sergeant Swanton rejected the comment. "I'll tell you that statement is absolute fabrication. That is not true," he said.