Ladysmith, South Africa (CNN)The killing happened in broad daylight.
It was Mandela Day, a day many South Africans dedicate to helping others.
Khanyisile Ngobesi-Sibisi's car was full of blankets to donate to charity, but as she drove around a bend near the edge of this small town, a white car pulled up alongside her convoy.
"She was following me from behind. I heard the first gunshot; not knowing my mother had been shot. Then I heard the second gunshot," says Zamokuhle, her 18-year-old son.
Two gunmen shot Khanyisile eight times through the driver's side door and window, according to witnesses.
"I can't explain the feeling I was having," Zamokuhle says. "I was shocked by disbelief that my mother had been shot."
Zamokuhle applied pressure to his mother's multiple wounds, but to no avail; she died at the scene.
Bright future cut short
Khanyisile was a popular figure in Ladysmith -- a teacher at the local primary school, and a life-long member of the African National Congress (ANC).
Many here saw a bright future for her.
She was standing as a Ladysmith councilor in South Africa's upcoming election, and her face smiles proudly down from the election posters still hanging on the street where she was murdered.
"Vote ANC," they read.
"My mother told me that someone warned her not to go to the Mandela Day event," says Zamokuhle.
Ladysmith's indoor stadium is packed with hundreds of mourners clad in the ANC's traditional colors: green, black and gold.
A relative of Khanyisile steps up to the microphone, "Yes, some of you are mourning, but some of you are celebrating. Because you did this."
ANC politicians targeted
Khanyisile was just the latest victim in a series of unsolved murders of ANC politicians in KwaZulu-Natal.
In the run-up to this election, more than a dozen politicians have been killed in this province: shot while watching TV; killed taking their children to school; ambushed on the way home from political meetings.
Not a single case has been solved.
"We are making progress. It just takes time," says Brigadier Hangwani Mulaudzi a spokesman for the Hawks, the country's specialized investigation division.
Several former investigators from South Africa's police told CNN that ANC members could be killing rivals to access elected government positions. The positions can mean access to corrupt wealth, they said.
Even the ANC's leadership admits the party is wracked by factional infighting.
"These killings are just the tip of the iceberg, people are killed when people can't be coerced by other means," says David Bruce, an independent researcher who studies violent crime.
"It says a lot about how politics takes place and politics is organized. Access to political office is not just a means of making a living. It is a way of establishing and maintaining networks of patronage," he says.
Kickbacks and corruption
Corruption watchdogs blame so-called "tenderpreneurs" -- individual councilors who get kickbacks for awarding dodgy government contracts -- for fueling corruption at the local level.
All of the country's political parties, including the ANC, say they are committed to stamping out corruption.
The factional fighting is embarrassing for the party that has ruled South Africa since the country's first democratic election in 1994.
Many believe that they face their sternest test yet in Wednesday's local government elections.
Polling has consistently shown that the ANC could lose ground, or even lose power in key cities like Tshwane, Nelson Mandela Bay and even Africa's business hub, Johannesburg.
Campaigning has been a tough fight between the ruling party and the official opposition Democratic Alliance (DA), a liberal party that has tried to broaden its appeal to traditional ANC voters.
The ANC has lost support in certain key urban areas to the Economic Freedom Fighters (EFF), led by charismatic populist Julius Malema.
History of violence
A series of corruption scandals involving President Jacob Zuma and a moribund economy has hurt the ANC's election campaign.
But in much of KwaZulu-Natal, the party is expected win with relative ease.
That makes the killings here even more disturbing for ANC politicians who have lived through darker times.
In the late 1980s and early '90s, supporters of the ANC and rival Inkatha Freedom Party were locked in a virtual war for support, with the hidden hand of South Africa's apartheid security services.
Thousands died in that struggle for supremacy.
"We have gone through serious violence in [KwaZulu-Natal]," says ANC provincial chairperson Sihle Zikalala."We had reached a point where we thought that such things were no more, would not happen again."
This time the killings seem to be within their ranks.