Clayton Kippie, 37, was shot five times by gunmen while walking home from a tuck shop.
Clayton recently joined the Alpha Neighbourhood Watch in Lotus River, but relatives believe his murder has nothing to do with his crime-fighting.
They say the motive is personal.
Clayton divorced his wife four months ago and has a 14-year-old son.
Following his divorce, he moved back to his family home in Lotus River.
Clayton had been walking back home on Thursday night after buying a los entjie at a tuck shop in 5th Avenue when he was confronted by gunmen in two cars, a Toyota Hilux bakkie and VW Polo Vivo.
The family says they have seen CCTV footage of the murder which was handed over to police to help in the investigation.
The Daily Voice was also shown the footage, showing Clayton casually walking down the street.
Two doors away from his home, the two cars stop next to him and the occupants open fire.
One of the gunmen then climbs out of the vehicle and fires more shots into Clayton as he lies bleeding on the ground, to make sure he is dead.
Clayton was shot a total of five times.
One of his three brothers, who asked not to be identified as he is also a member of the Alpha Neighbourhood Watch, says they are certain the murder was planned by someone “close to Clayton”.
“It was around 8pm when the shots went off and one of my brothers, who was at home, ran outside and saw him lying there,” the man explains.
“He left home to get a loose cigarette. Clayton was a peaceful guy who recently got divorced and moved back to our parents’ home.
“They shot him two doors away from his home. He was shot five times.
“Our brother was not a gangster. We have seen the footage and we do believe this was a hit.
“The footage tells us this. This was not because he was a neighbourhood watch member, this was due to personal reasons.
“But we do not want to say too much while the police are busy with their investigation.”
Another brother, Cedric Kippie, says they are devastated: “This was so unnecessary and what can we do now but lay him to rest.”
Police spokesperson Sergeant Noloyiso Rwexana says cops are working around the clock to make an arrest: “He died on the scene due to his injuries. A case of murder was opened for investigation.”