The bulletin, reportedly based on information from an informant, said members of the gang who are in the military will supply grenades and explosives, CNN reported.
The purported threats, such as running over officers at traffic stops and car bombs, targeted the McLennan County Jail in Waco as well as sites in Austin, El Paso, Dallas, Corpus Christi and Houston.
CNN said the DPS did not respond immediately for comment on the report.
Police arrested about 170 people at the time of the shooting, charging them with felony counts of engaging in organized criminal activity and set their bonds at $1 million. Police said they confiscated at least 318 weapons, including clubs, knives, brass knuckles, firearms, and chains with padlocks attached to them.
Police described the confrontation as a turf battle between two warring gangs.
"These were vicious criminals that knew that they were in trouble, and they were trying to dispose of evidence," Waco police spokesman Sgt. W. Patrick Swanton said.
The killings in the central Texas town, however, have also prompted scorn on some social media and conspiracy websites that call the fracas a "police massacre" at a gathering of peaceful bikers.
One biker blogger who calls himself The Aging Rebel charges flatly that police statements on the killings are "fabrications."
"There were no threats. Murders of, and even assaults on, sworn peace officers in the United States by outlaw bikers are extraordinarily rare. In the United States, policemen are more likely to be struck by lightening (cq) than to be punched by a motorcycle outlaw," he writes.
Some readers on the site also claim that pre-positioned police did all the shooting and suggest the confrontation may be a trigger for a martial law crackdown by U.S. Army troops already in Texas to conduct summer training exercises codenamed "Jade Helm 15."
A reader — posting on the Aging Rebel website as "M.E." — called on the biker community to do more self-policing to give "big brother" less of any excuse to step in.
"Take into account the political climate and the current administration, and I guarantee you that you're going to start seeing a lot of our ability to enjoy our lifestyle on two wheels, whether it be as an independent or in a club, eroded seriously over time," M.E. writes.
Swanton, the Waco police spokesman, dismissed such sites.
"We would like to remind all that selective videos and cropped photos DO NOT paint a complete picture of what actually occurred," Swanton said. "Law Enforcement has video as well but it is preserved for evidence. We play by a very strict set of rules and will not deviate from them to match attempts to sway the truth. I can attest I have personally seen the horror unfold and was amazed at the actions of our heroic officers in their quest to save innocent victims lives."
Video footage reviewed by the Associated Press shows that when gunfire erupted in the parking lot of the restaurant, most of the bikers watching the confrontation from the patio or inside immediately ran away from the shooting. A few tried to direct people to safety, crawling on all fours heading for cover.
Restaurant security video reviewed exclusively by the AP on Wednesday showed only one of the dozens of bikers recorded firing a gun from the patio of the restaurant. None of the nine video angles shows the parking lot.
Waco police say they did not have any police inside undercover because Twin Peaks, the restaurant where the shootings occurred, was not cooperating with authorities who had tried to warn of the danger of a confrontation.
The national corporate leaders of the chain quickly revoked the local franchise, saying on Facebook that the restaurant's local management in Waco "chose to ignore the warnings and advice from both the police and our company, and did not uphold the high security standards we have in place to ensure everyone is safe at our restaurants."
Jay Patel, operating partner at the Waco franchise, denied the charge, saying on the local restaurant's Facebook page that "our management team had had ongoing and positive communications with the police."
