Bob Knight ... killed by a stray bullet.

Bob Knight ... allegedly killed by a stray bullet.

Some witnesses giving evidence in a murder trial over the death of a truck driver may have lied on oath because they feared being labelled ‘‘dogs’’ within their community, a jury has been told.

In the NSW Supreme Court today, the Crown prosecutor, Pat Barrett, said a number of witnesses had been ‘‘obstructive, aggressive, unwilling’’ and some ‘‘had very little regard for the oath they had sworn to’’.

Some of them put on quite significant performances before you in this trial 

Bob Knight, 66, from Canberra, was allegedly killed when a stray bullet fired during a gunfight between two rival groups in a KFC car park struck him in the head as he waited at a set of traffic lights at Milperra, in Sydney’s west, on June 25, 2009.

Three men - Mahmoud Mariam, 28, Adel Elkobali, 21, and a 20-year-old man - who cannot be named as he was a juvenile at the time - are on trial for murder and affray. They deny the charges.

In his closing address to the jury, Mr Barrett said the Crown case was that Mr Mariam fired the fatal shot from a Ruger pistol, but all three men were liable for Mr Knight’s murder.

The juvenile, a member of the ‘‘Elkobali’’ group, had been involved in a clash with a teenage member of the rival ‘‘Mariam’’ group at the Bankstown Centro shopping centre earlier that evening, the court heard.

A flurry of phone calls followed, which Mr Barrett likened to ‘‘marshalling the troops’’, and the two groups arrived at the car park armed with firearms.

In the ensuing shoot-out, one bullet travelled out of the car park, through the trees, across Milperra Road and into the truck, fatally striking Mr Knight, the court was told.

To find the accused guilty of Mr Knight’s murder, the jury had to be satisfied that each man intended to inflict grievous bodily harm on any other person, Mr Barrett said.

‘‘Mr Knight wasn’t an intended victim. He was unknown to all the people at the KFC outlet. But nevertheless, persons can still be liable for his murder if the act was done with the relevant intention,’’ he said.

The jury did not have to determine who fired the fatal shot, but they also had to be satisfied the men were part of a joint criminal enterprise, the court heard.

During the 10-week trial, some of the witnesses ‘‘put on a performance’’, claiming their statements to police had been altered or they had been the victim of police brutality, which police denied, Mr Barrett said.

‘‘They might [believe] if they gave evidence they might be regarded in their community as ‘‘dogs’’, whether that’s real or imagined,’’ he said.

The term was slang for police informants, he said.

The trial continues.