Who was involved in the deadly Waco biker brawl?

“In 34 years of law enforcement, this is the most violent crime scene I have ever been involved in,” Waco Police Sgt. W. Patrick Swanton said following a biker gang shootout that left 9 dead and 18 others wounded in the parking lot of a busy shopping center Sunday. “There is blood everywhere.”

Reports of the grisly brawl, which police said escalated from the bathroom to the bar and out into the parking lot of a restaurant called Twin Peaks, sound like a scene from a movie — or one of the countless scripted and reality TV shows about the elusive world of biker gangs. More than 170 people were arrested on charges of engaging in organized crime in relation to the shooting which, Swanton clarified, constituted “capital murder.”

In a press conference Monday, Swanton said that five gangs had been identified in the deadly altercation, but added that he was "not about to give them the respect of giving you their names.” While Swanton insisted that the Waco police would continue to refrain from naming the groups so as not to “give them publicity,” earlier reports on the shooting pinpointed at least two gangs at the center of the chaos: the Bandidos and the Cossacks.

A McLennan County deputy stands guard near a group of bikers in the parking lot of a Twin Peaks restaurant Sunday, May 17, 2015, in Waco, Texas. Waco Police Sgt. W. Patrick Swanton told KWTX-TV there were "multiple victims" after gunfire erupted between rival biker gangs at the restaurant. (Rod Aydelotte/Waco Tribune-Herald via AP)
A McLennan County deputy stands guard near a group of bikers in the parking lot of a Twin Peaks restaurant Sunday, May 17, 2015, in Waco, Texas. Waco Police Sgt. W. Patrick Swanton told KWTX-TV there were "multiple victims" after gunfire erupted between rival biker gangs at the restaurant. (Rod Aydelotte/Waco Tribune-Herald via AP)

The Bandidos

With up to 2,500 members across 13 countries — 900 of them in the U.S. alone — the Bandidos are considered one of the country’s largest outlaw motorcycle gangs and “a growing criminal threat” by the Department of Justice.

Bitter rivals of the Hells Angels, likely the best-known biker gang in the U.S., the Bandidos are involved in the transportation and distribution of cocaine and marijuana as well as methamphetamine, which they also produce. The gang is also actively expanding its presence across Texas, where its membership is largely concentrated, and throughout other parts of the country, starting new chapters and recruiting members of allied clubs.

RELATED: Waco biker gang shootout photo gallery

The Texas Department of Safety’s 2014 gang threat assessment included the Bandidos among the Aryan Brotherhood, the Crips, the Bloods and other “Tier 2” threats — the second highest.

Bikers congregate against a wall while authorities investigate a Twin Peaks restaurant Sunday, May 17, 2015, in Waco, Texas. Waco Police Sgt. W. Patrick Swanton told KWTX-TV there were "multiple victims" after gunfire erupted between rival biker gangs at the restaurant. (Rod Aydelotte/Waco Tribune-Herald via AP)
Bikers congregate against a wall while authorities investigate a Twin Peaks restaurant Sunday, May 17, 2015, in Waco, Texas. Waco Police Sgt. W. Patrick Swanton told KWTX-TV there were "multiple victims" after gunfire erupted between rival biker gangs at the restaurant. (Rod Aydelotte/Waco Tribune-Herald via AP)


The Cossacks

Less is known about the Cossacks Motorcycle Club, a local Texas gang reportedly founded just three years after the Bandidos, in 1969. But early expert analyses suggest rising territory-related tensions between the two Texas groups may have been at the root of Sunday’s shootout.

In 2013, Jack Lewis, the president of the Bandidos chapter in Abilene, Texas, was arrested in the nonfatal stabbings of two Cossacks members.

Steve Cook, executive director of the Midwest Outlaw Motorcycle Gang Investigators Association and a Kansas City law enforcement officer who says he previously worked undercover in the Bandidos, told both Vox and the Washington Post that the Cossacks may have been pursuing an alliance with the Bandidos’ rivals the Hells Angels in an effort to challenge the larger gang’s control of Texas.

"We knew the tensions with the Cossacks were as high as they'd ever been," Cook told Vox. "I don’t think anybody could have forecast it to the degree that it happened."

Police officers stand watch from the roof of the Twin Peaks Restaurant in Waco, Texas May 18, 2015.  Police braced for retaliation attacks after 170 people were charged on Monday in connection with the shootout among motorcycle gangs a day earlier that left nine dead and 18 wounded at the Twin Peaks restaurant turned into a blood-soaked crime scene.  REUTERS/Laura Buckman

Twin Peaks

After the dust settled on Sunday, the Associated Press reported that the inside of Twin Peaks, the restaurant where the brawl had begun, “was littered with bullet casings, knives, bodies, and pools of blood.”

Police said the Twin Peaks’ management had been aware that a planned meeting of around 200 outlaw motorcycle gang members at the local restaurant would likely erupt but had refused to cooperate with law enforcement in trying to prevent the kind of violence that took place Sunday.

Amid threats from bike gangs around Texas that prompted heightened security in parts of Waco Monday, the Texas Alcoholic Beverage Commission closed Twin Peaks for liquor sales for a week.

"That's a good thing for law enforcement here,” Swanton said. “That is one issue that we don't have to worry about people coming in and creating another incident after the tragic incident we had last night."

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