A Pretoria arms dealer, who also worked as a police reservist, has been gunned down in a suspected hit close to his home.

Ivan Monsieur, 56, a police reservist at the Midrand police station, was shot dead this week while en route to his office in Lyttelton.

Monsieur was off-duty when he was shot. He was the chief executive of New Generation Ammunition (NGA), an ammunition manufacturing and weapons importing and exporting business which he had owned for 17 years.

NGA supplies ammunition, mainly to gun shops, and weapons for local security companies and various southern African government law enforcement, security and justice departments.

At least one of the two bullets which hit Monsieur, a registered arms dealer, is believed to have been from an execution-style shot to the head.

Nothing except his personal firearm was stolen. Monsieur was found lying near his bakkie, which he had stopped on Olifantsfontein Road next to a cabbage field.

Monsieur was shot when he was stopped by two men, who were apparently wearing metro police uniforms, close to his Midrand home.

It is believed the men were driving a white Toyota Corolla which was fitted with an emergency-vehicle siren.

Police said on Thursday that according to labourers working in fields next to Monsieur's car, a person in the Corolla had sounded the siren.

Inspector Mmakgomo Semono said that when the workers heard the siren, they looked up and saw two men, apparently in metro police uniforms, step out of the car and then shoot the man who had walked up to their car.

He said it appeared as though Monsieur was shot in the top of the head as he collapsed to his knees and fell to the ground.

"The only thing that was taken was Monsieur's gun. His wallet, cellphone and bakkie were left by his killers," Semono said.

He said the docket had been handed over to detectives from the Johannesburg Organised Crime Unit.

Asked why that unit was investigating the case, Semono said the investigation had been handed over to the Organised Crime Unit because of the nature of the attack.

He added that the possibility of a hit could not be ruled out.

"Everyone has enemies - some of whom you do not even know," he said.

Police were following up on information and were hoping for a breakthrough soon.

NGA general manager Henry Wiggins, asked if knew of a possible motive for Monsieur's murder and whether he had any enemies, said he was a very competitive businessman.

"Not everyone likes that," he added.

Wiggins said they were unsure whether the murder was related to Monsieur's private business or his work as a police reservist.

"I do know that he hated corruption with a passion and would go out of his way to report those who he thought were crooked," he said.

He said the staff were devastated by the murder.

"Although it is a serious loss we are going to continue to trade," he asserted.

Semono has appealed to anyone with information on the killers' identities to contact Crime Stop on 0860-010-111.

With acknowledgements to Cape Argus.