Nine people died in Waco, Texas, in May after a shootout between warring motorcycle gangs at restaurant car park - but is such violence an aberration or part and parcel of such groups?

"Look at it now, it's such a tranquil place. It was the same that Sunday afternoon, until all hell broke loose."

McLennan County Sheriff Parnell McNamara stands outside the Twin Peaks restaurant in Waco, the scene of a deadly shoot-out between biker gangs. He points to where the carnage happened.

"You could see bodies lying about - one was right there on the grass, five here on the parking lot, one over there behind that pick-up truck."

McNamara does not hide his contempt for the men involved.

"They couldn't have cared less about the families right across the parking lot in other restaurants or shops," he says. "All they were interested in was killing rival bike gangs."

All of those killed and injured were part of biker gangs who had arranged to meet at the restaurant.

More than 170 bikers were arrested. Most are still in prison, with members of the different gangs being detained separately from each other.

Image copyright AP Image caption The feud broke out between several gangs at a shopping district in Waco

After some persuasion, we managed to speak to a biker who was moments away from having been caught up in the bloodshed. He had been heading to Twin Peaks, but was stuck in traffic when he heard what had happened.

"We were just as shocked as anybody else," says Sean, who spoke to us on the condition we only use his first name.

A few hours south of Waco, Sean invites us to attend the funeral of a friend of his, Jesse "Mohawk" Rodriguez. one of the bikers who died in the car park,

Hundreds of men in leathers are there, their bikes parked beside the church.

They hug each other, support the grieving family and ultimately congregate in individual groups, denoted by the insignia on their jackets.

As the coffin is brought out of the hearse, a large proportion of the bikers salute.

Many of them, like "Mohawk", Sean and thousands of bikers around the country, used to serve in the American armed forces.

"It's about camaraderie, it's about brotherhood, getting together with like-minded individuals," Sean says, explaining why so many bikers are former military.

"When you're in the military, you're really, really close to the people you serve with and when you come back there is a hole."

But another former biker, James Quinn, a professor at the University of North Texas, says when mixed with disillusionment, such biker clubs can often go beyond just men hanging out together with their bikes.

Image caption James Quinn used to belong to a motorcycle club himself

"They are very loyal to their insignia, to their brothers - and very territorial," Quinn says, adding the groups are a "great place" to set up criminal networks - "drugs, weapons, extortion and prostitution are the mainstays".

Police investigators say the killings at Twin Peaks were about a challenge over territorial control.

The dominant gang in a state (currently the Bandidos in Texas) can demand affiliation from smaller clubs in return for protection and the use of the state name on their insignia, Quinn says, adding smaller clubs may not be directly involved in criminal activity.

All of the bikers we spoke to at Mohawk's funeral said they were disappointed in the negative portrayals of bikers, saying accusation of links with criminality were far-fetched.

But when a veteran member of the Bandidos, a group that classifies itself as an "outlaw motorcycle club" arrived to pay his respects, many of those same bikers showed deference.

Image copyright AP Image caption A police officer stands guard near bikers after the shootout

"If you lay down with dogs, you're going to get fleas," says Steve Cook, who worked as an undercover investigator in outlaw motorcycle gangs, and now trains law enforcement.

He goes further than many other experts, saying the vast majority of motorcycle clubs in the United States in some way support those bikers involved in criminal activities.

"As time goes by, they get a little bit more involved with the outlaw groups are doing and before you know it you have these guys getting involved in stuff like you saw in Waco," Cook says.

"The groups that don't placate these guys are few and far between."

The bikers we spoke to say the level of criminal activity Steve Cook alleges is not borne out by the number of arrests of bikers over the years.

Image copyright AP Image caption Bikers ride as a part of protest against what they say is the violation of rights of many bikers who were arrested just for being at the scene of the killings

But Cook believes that is due to romanticism that surrounds motor biking in the United States.

"Even within law enforcement here there is that romanticism about bikers," he says.

"Officers don't pay any attention to the crimes bikers commit at all, they don't take them seriously."

Sean feels the popular perception of bikers, especially in movies and television, go against them, focusing on violence and criminal activity.

"We're people who pay our taxes, have normal jobs, raise our kids," he says.

After the church service, uniformed Marines perform military rites beside the coffin.

As the hearse is pulled away by a Harley Davidson, the scores of bikers at the funeral mount their motorcycles and follow behind in a thunderous "last ride" for Mohawk.