First they killed Omairi's daughter. The paramilitaries meant to kill her husband, a journalist who was exposing corruption in Colombia, South America. They bungled the assassination and he survived, but their daughter died. That was 22 April 2004, their daughter's twentieth birthday. More than eight years later, just one person has been questioned about her murder – and, the authorities being past masters at delaying justice, that person has still not been charged, but is 'under investigation'.

In 2009, they killed Omairi's son and stepson. This time the paramilitaries went to their house. Her husband wasn't there, but the sons were and they gunned them down. Nobody has been charged. A year later, Omairi's husband died from 'natural causes'. The stress, the knowledge that he was the indirect cause of his children's death and the constant threats had all taken their toll. His mind and body, his widow Omairi Maldonado Diaz says, had simply said: 'Enough'.

She is the sole survivor of the family and I met her last week in the northern Colombian city of Bucaramanga. She is now in voluntary exile in Venezuela, but came back to Colombia to meet me and the other members of the Colombia Caravana, a charity that works to support and protect lawyers working in that troubled South American republic. How can all this have happened to Omairi's family simply because someone disapproved of what the father has written? Where are the lawyers and human rights defenders?

Well, 50 of them have been murdered in the last 12 months, so maybe the survivors have been keeping their heads below the parapet. You can't really blame them: the rule of law was an early victim of the decades of civil war that afflicted Colombia's recent history. The country is cursed with the good fortune of massive reserves of natural resources. It has gold, emeralds and oil. The soil is rich and ideal for agribusiness to cultivate bananas and palm oil. Rivers are plentiful and ripe for damming for hydroelectricity. And it is also the world's largest producer of cocaine.

The result is a country racked by bloody confrontations between Marxist guerrillas, government forces and privately raised paramilitary groups, all trying to get their slice of the pie by land grabbing or running the drugs trade. Colombia's hapless farmers and indigenous peoples, caught in the crossfire, have suffered tens of thousands of murders, 'disappearances' and unlawful detentions. Some 3m are believed to have been displaced to live in shanty towns on the edge of cities. People who speak out against the corruption and murders, like Omairi's husband, become targets – and their families, like Omairi's family, often get caught in the crossfire.

The Marxist guerrillas have now been largely defeated, in part thanks to billions of dollars of military aid from the US, but to this day some towns and great swathes of countryside are still controlled by the paramilitaries. These are areas where the state can do little to protect its citizens and where the paramilitaries act with impunity. So what has this history lesson got to do with the tragic story of Omairi's family? Her husband, in a small way, was doing what he could do to redress the balance in favour of justice. He had exposed links between politicians and the paramilitaries in the north of Santander, the province in which Bucaramanga lies.

Since his death, a former provincial official – a mayor, but with more power and influence than our mayors – has been jailed for his involvement in corruption and murder. A former army colonel has been charged for his part in two assassinations, but has now – like Omairi – sought refuge in Venezuela. And a former paramilitary leader, Jorge Ivan, now in prison, has admitted his participation in the 2004 assassination attempt that killed Omairi's daughter. He is the only person currently being investigated for any of the murders – but then the state is a past master at almost indefinitely stalling trials that might reveal embarrassing details.

The judiciary is on the side of the angels, but the real power lies elsewhere, with politicians who pass laws to benefit themselves and paramilitaries who support them, at a price. At the end of the interview, I again thanked Omairi for returning to Colombia to see us. She is an amazingly brave woman, but even she replied: 'I am afraid to be here. The paramilitaries are free on the streets and they know what I look like. I am afraid.'

  • A collective of lawyers, the Corporacion Colectivo de Abogados Luis Carlos Perez, is acting for Omairi and was also my host (and minder!) in Bucaramanga. The collective is funded by the European Union, charities and other organisations. There is no legal aid in Colombia.

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