First came a few pistol shots, several witnesses said, then a barrage of rifle fire during the shootout last month at a Waco restaurant favored by bikers.

But authorities still have not said how many of the dead and wounded were the result of police fire.

Police have identified only one assault weapon, a semi-automatic gun that fires high-powered ammunition, among the firearms confiscated from bikers, and that was found in a locked car after the shooting ended.

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Aftermath: Law enforcement officers are pictured on the day of the Waco, Texas, biker shootout speaking to more than a dozen gang members and sifting through evidence at the site of the gun battle which left nine dead

But several witnesses - at least three of them veterans with weapons training - say that semi-automatic gunfire dominated the May 17 shootout that left nine dead and 18 wounded.

'I heard, "pop, pop" small caliber, and then a rapid succession of shots from what sounded to me like an assault rifle,' said William English.

The former Marine and Iraq war veteran was approaching the front door of the Twin Peaks restaurant for a meeting of biker clubs at the time.

Gunfight: An officer is seen above wielding a rifle while bikers are kept on the ground during the confrontation. Witnesses who have been trained in firearms suggested that semi-automatic weapons dominated exchanges

Mystery: witnesses who were at the shooting said they heard mainly semi-automatic weapon fire - a puzzling fact as police have so far only spoken on recovering one semi-automatic rifle from the scene

It's remains unclear exactly what triggered the gunfight.

More than 100 of the 170 people arrested, mostly bikers and family and friends, are still in custody and cannot give their accounts.

Six witnesses have described a melee that began with a few pistol shots but was dominated by semi-automatic gunfire.

Waco police have said they returned fire after being shot at, and call the witnesses' depictions of events incorrect.

While those with pending charges may benefit by blaming authorities, police have declined to release detailed reports from that day and say they are still awaiting ballistic reports.

Mugshots: 170 people were arrested after the gunfight, many of whom are still in custody. Above are 35 of them

English said shots came from the restaurant's patio as he and his wife approached the building.

They and other members of their Distorted motorcycle club took cover on the opposite side of the patio.

Steve Cochran, a Navy veteran and member of the Sons of the South club, pulled into the parking lot facing the patio minutes before the shooting began.

He was to help set up for the meeting of the Confederation of Clubs and Independents, a group that advocates for biker rights and motorcycle safety.

'I heard one pistol shot. All the rest of the shots I heard were assault rifles,' said Cochran, who took cover behind a crane about 30 yards away.

He walked the shooting scene with reporters several days later, showing what he saw and his vantage point.

Investigation: Police and firearms experts are still probing the specifics of the firefight, and have enlisted a ballistics lab to analyse seized wepaons

Cochran said he heard suppressed rounds fired by assault weapons, which are still audible but sound different than a handgun firing.

Police have said 18 officers, four state troopers and more than 200 bikers were at Twin Peaks at the time.

Investigators have said the shooting began during an apparent confrontation between the Bandidos, the predominant motorcycle club in Texas, and the Cossacks, then spilled into the parking lot.

Video footage of the shootout shows that it began outside.

Ron Blackett, a Confederation of Clubs and Independents leader who is a former Army and Coast Guard officer, also reported hearing one or two pistol shots followed by a blast of assault rifle fire from where he was parked in a lot behind Twin Peaks.

According to records released after a public information request for 911 calls, Officer Brandon Blasingame reported 'shots fired,' to a dispatcher at 12:26pm.

Clash: The bikers opened fire in the parking lot of the Twin Peaks restaurant in Waco, Texas

'Two shot behind Twin Peaks,' Blasingame reported two minutes later.

'They have an AR-15,' he said in the next dispatch. It was unclear who he meant had the rifle, and whether it was something he saw or was told.

The chronology ends at 12:31 p.m. and police have refused to release the rest of the report, saying it could compromise the investigation. Blasingame did not respond to requests for comment.

A Waco police spokesman said the witnesses' depictions of events are 'absolutely incorrect,' asserting that police shot fewer rounds than the bikers.

BLOODBATH AT TWIN PEAKS: THE VICTIMS Cossacks Richard Matthew Jordan II, 31 Jesus Delgado Rodriguez, 65 Charles Wayne Russell, 46 Daniel Raymond Boyett, 44 Wayne Lee Campbell, 43 Jacob Lee Rhyne, 39 Richard Vincent Kirschner Jr., 47 Matthew Mark Smith, 27 Bandidos Manuel Issac Rodriguez, 40 Advertisement

He confirmed that some officers carry semi-automatic weapons, which fire a single shot with every pull of the trigger, and automatically reload between shots.

Jennifer Cicolani, of the Bureau of Alcohol, Tobacco, Firearms and Explosives, noted that a semi-automatic gun can shoot more bullets in less time than a small-caliber weapon.

Waco police declined to say whether assault weapons beyond the AK-47 in the car had been seized, reiterating that 318 weapons were collected, including that gun, handguns, brass knuckles, knives and chains.

Waco police have sent the weapons to a ballistics lab in Washington, D.C., and say it could take months to get results to show which bullets struck the dead and injured.

After the melee, police records show officers rounded up anyone suspected of being part of a biker gang, targeting those in leather vests and patches. Neither Blackett nor Cochran was arrested.

English and his wife were, and were held for more than two weeks before being released on $25,000 bail.

'One of the sheriff's officers said we were going to be interviewed and turned loose,' said English, who was wearing a leather vest that day with the name of his club on it.

Nearly all of those arrested were charged with engaging in organized crime, a felony.

About 60 people had bonded out by Thursday, but those with the closest views of the shooting remain in jail and cannot talk, according to the bikers' attorneys.