Five decades ago, Le Hien Duc worked as a military decoder for the army of Ho Chi Minh in its battle against the French colonial forces. Now aged 75 and with eight grandchildren, she is leading the fight against corruption in Vietnam, a nation with a serious corruption problem but where few ordinary people are willing to stand up against it.
She has received warnings from her friends and death threats from anonymous strangers, yet nothing can persuade her to end the struggle. "People have told me not to spend my money on phone calls and to start saving for a coffin instead," said the former primary school teacher.
This week her role as a fighter against bribery and a crusader against corruption was further cemented when the watchdog group Transparency International (TI) chose her as winner of its annual integrity award.
The Berlin-based group said Ms Duc had displayed remarkable courage as she set about tackling corruption at all levels of Vietnamese life. "Her respect for authority ends where corruption begins. Duc has tracked down high and low-level officials ... at home or in the office, to ensure that they cannot ignore the victims of corruption claiming their rights," it said. "In spite of many threats, she provides hope and encouragement for stopping acceptance of corruption."
Since she retired from teaching in 1984, Ms Duc has worked from her Hanoi home writing countless letters and emails and making endless telephone calls in pursuit of government officials and others. Her home is piled with letters from ordinary members of the public seeking her help.
Those she has targeted range from school officials who have short-changed school children on their meals to a water company that charged residents for purported improvements that it never made.
In one case she telephoned a minister 30 times to force the issue. In another she pursued a Hanoi traffic policeman she had witnessed demanding a bribe, chasing him with her digital camera to record his badge number. Eventually she was able to lodge a formal complaint with the police chief that resulted in the errant officer being demoted. "Many police now carry my photo in their wallets so they can recognise me on the street," she told the Agence France-Presse.
Ms Duc has made plenty of enemies. She will not allow either her grandchildren or her four children to visit her at home for fear they could become victims of an attack on her.
The group TI, which split the award between Ms Duc and Mark Pieth, a criminal law and criminology professor at the University of Basle in Switzerland who was a member of the investigation into the Iraq oil-for-food scandal, said Vietnam ranked 123 out of 179 in its Corruption Perceptions Index, a survey of business people's experiences of corruption around the world.
Ms Duc said she is convinced her fight against corruption will be successful. "During the war against the French, I fought against injustice. Now that I'm retired, I have more time to fight injustice," she said. "Vietnam has won every war it has fought ... There is no reason it cannot win the war against corruption."