Caribbean Fever - Your ONLY destination to all things Caribbean and more
Scroll down for the video. GRAPHIC CONTENT WARNING
Classmates: Chiadika Biringa (top), 20, studied theatre arts while Tekena Elkanah (bottom), 20 was a technical student. The four traveled to Aluu to collect a debt
When best friends Ugonna Obuzor, Chiadika Biringa, Lloyd Toku, and Tekena Elkanah left their Nigerian university campus for a nearby village to collect a debt, none could have known they were walking towards a death of unutterable brutality.
They were chased through the streets by stick and stone-wielding vigilantes, stripped naked and beaten until they were almost unconscious.
They were dragged through mud, had concrete slabs dropped on their heads and car tyres filled with petrol wrapped around their necks. Then somebody lit a match.
Close: Lloyd Toku (left), 19, was a civil engineering student and Ugonna Obuzor (right), 18, was a geology student. They were stripped naked and beaten until they were almost unconscious, had concrete slabs dropped on their heads and tyres filled with petrol wrapped around their necks
This horrific orgy of violence and torture was also be filmed on a mobile phone and later uploaded to YouTube for the world to see.
It is known as 'necklacing', the appalling method of killing which involves putting a petrol-filled tyre around a victim's neck and setting it ablaze, and this latest incident has sent shockwaves throughout Nigeria and the wider world.
It is a horrifying example of what can happen when respect for the law drains away and communities turn to mob justice to summarily execute suspected criminals.
Campaigners say police are largely to blame and are feared more than organised criminals in parts of Nigeria where faith in the judicial system has all but evaporated.
Unspeakable: The orgy of horrific violence and torture was filmed on a mobile phone and later uploaded to YouTube for the world to see
Fear: They were dragged through mud, had concrete slabs dropped on their heads and tyres filled with petrol wrapped around their necks. Then somebody lit a match
And experts say so-called 'jungle justice' is increasing in many of Nigeria's poorer, more isolated communities where the Nigerian authorities have failed to crack down on a culture of impunity for crimes.
Obuzor, Biringa, Toku, and Elkanah were roommates at the University of Port Harcourt, in Chuba, Nigeria.
According to Biringa's mother, Chinewe, Obuzor had asked his friends to accompany him to the nearby village of Aluu because somebody there owed him money.
What exactly happened when they arrived is unclear, but it has been claimed that Obuzor's debtor spread the word that the men were there to steal laptops and mobile phones and they were soon set upon.
'I want the world to know how our security failed us. I want the world to know that my son and his three friends are innocent of what they said they did,' Mrs Biringa told CNN.
'He was a very kindhearted boy and we (were) so close,' she said. 'If my son sees you 100 times he will greet you 110 times.'
Best friends: According to Biringa's mother, Chinewe, the four friends dreamed of launching a music career and had already recorded a song together called, Aint No Love in the City
A family's pain: Chiadika Biringa's parents and Chinewe and Steven say they watched the video because they wouldn't have believed it if they hadn't seen their son's killing with their own eyes
According to reports the village had been shaken by a series of recent armed robberies and villagers were on high alert.
But Mrs Biringa said the three friends were entirely innocent and dreamed of launching a music career. They had already recorded a song together called, Aint No Love in the City.
Mrs Biringa and her husband, Steven, an oil executive at Nigerian National Petroleum Corporation (NNPC), says that he watched the video because he wouldn't have believed it if he hadn't seen his son's killing with his own eyes.
Suspects: Thirteen villagers from Aluu are paraded by police in Port Harcourt. Among them was the village chieftain
Oil country: The four young men were studying at the University of Port Harcourt. Aluu is nearby
'I want them to know from beginning to end the barbaric nature with which they chose hunt them down,' he said. 'Even your worse enemy should not be treated in such form in the 21st century that people are still behaving and killing human beings as if they were rats.'
In the wake of the killing students at University of Port Harcourt (Uniport) rioted, burning cars, shops and houses.
'Necklacing' is the practice of forcing a tyre filled with petrol over victim's head and shoulders and setting it alight.
It can often take a victim more than 20 minutes to die in excruciating agony.
In the violent 1980s and 1990s, necklacing was a common sentence imposed by 'people's courts' on collaborators with the apartheid regime and criminals in South Africa.
It is still used in certain, more lawless, parts of Africa, where corrupt police are no longer trusted, to punish thieves and rapists.
Incidents have been reported more recently in Haiti, Ivory Coast, Nigeria and India.
Brazilian drug lords are also known to have 'necklaced' their enemies, most notoriously the journalist Tim Lopes in 2002.
He was kidnapped by local drug dealers while investigating crime in Rio's favelas.
His hands, arms, and legs were severed with a sword while still alive, and then had his body placed within tires, covered in gasoline and set on fire.
Anti riot police were called in and the campus was shut down indefinitely.
Spurred into action by the uproar surrounding the incident, Nigerian police have since arrested at least 19 people from the village of Aluu, including its chieftain Alhaji Hassan Welewa.
A police spokesman said: 'The police immediately launched an investigation leading to the arrest of Alhaji Hassan Welewa, the traditional ruler of Omukiri Community, Aluu, where the heinous incident took place and eighteen others, some of who are members of the vigilante group of the community.'
Police said officers on the scene were unable to prevent the sickening lynching because they were pelted with stones by villagers until they fled on foot.
In the violent 1980s and 1990s, necklacing was a common sentence imposed by 'people's courts' on collaborators with the apartheid regime and criminals.
It was frequently carried out in the name of the now-ruling African National Congress.
Now necklacing is being used across parts of Africa where law is seen to have failed. Incidents have been reported in South Africa against Zimbabweans and Mozambicans who have fled violence and poverty in their own countries.
In horrific attacks, mainly around Johannesburg, women have been raped and men beaten to death.
Shops and homes have been looted and dozens of shacks burned to the ground. Thousands of refugees have fled to the comparative safety of police stations.