Attackers gunned down a former senior union official at platinum producer Lonmin, stoking political and industrial tensions on South Africa's volatile platinum belt.
Police said the former National Union of Mineworkers (NUM) shop steward, Percy Letanang was ambushed outside his home in the mining town of Mooinooi on Sunday night and died of his injuries on Tuesday.
Letanang was shot seven times by unknown assailants. Police were investigating but had made no arrests yet, police spokesperson Thulani Ngubane said.
He was the fourth person in the region with links to the NUM to have been murdered in the past three months.
Tens of thousands of NUM members were poached last year by a new rival, the Association of Mineworkers and Construction Union (Amcu), in a turf war that killed dozens of people and sparked widespread industrial unrest.
Lonmin, the world's third largest platinum producer, was at its epicentre. Police shot dead 34 striking workers at its Marikana operation in August 2012, the deadliest security incident since the end of apartheid.
Industrial action in the mining region northwest of Johannesburg has been less violent this year but members of both unions are still being killed and gangland style slayings are a common feature of the shanty towns that ring the mines.
The killings come as the NUM is trying to lay the groundwork to retake the platinum belt, a campaign with high political stakes for the ANC as the party looks to rally support ahead of general elections due next year.
Cosatu, the umbrella union which NUM falls under, said in a statement that Letanang had taken a voluntary severance package recently after Lonmin recognised Amcu as its majority union. A Lonmin source confirmed this was the case.
"Cosatu is outraged by the continuation of what are clearly deliberate assassinations of NUM members in the area, and the failure of the police to arrest most of the perpetrators and bring them to justice," it said.
Three weeks ago, a senior NUM official at Lonmin was also gunned down in a hail of bullets at Marikana.
Over 7 000 NUM members are currently on strike at mid-tier platinum producer Northam and its demands of pay hikes of up to 43% signal it is trying compete with AMCU, which has attracted members with its militancy.