Zahra Bani Yaghoub was sitting on a park bench chatting to her fiancé when Iranian religious police arrived and arrested the couple. They were carted off to jail and held in separate cells. The fiancé was released but the body of Ms Bani Yaghoub, a 27-year-old doctor, was delivered to her family two days later.
Under President Mahmoud Ahmadinejad, Iran's feared morality police have been acting with renewed vigour against what they consider to be unIslamic behaviour. Although the doctor's death last October is widely known among Iranians because they have internet access, the case received only a brief mention in the state-run media.
Shirin Ebadi, a Tehran-based lawyer who won the Nobel Peace Prize in 2003 for her tireless defence of human rights, is now seeking justice in the case.
Yesterday, she warned that the morality police, who frequently stop women in the street to accuse them of wearing headscarves that are too skimpy, are now threatening to enter the offices of private companies in their Islamic zeal.
Ms Ebadi also said that human rights in Iran had regressed over the past eight years – from the persecution of homosexuals to the recent arrests of leaders of the Bahai religious sect, to bus drivers jailed for protesting over low pay.
Speaking in London, the Nobel laureate said: "They claimed [Ms Bani Yaghoub] committed suicide in prison, which is a lie. In prison they even take your watchbands and shoelaces from you. Her family believes she was tortured and died as a result. That's my reading, too.
"Whatever they do is illegal. The question is who is responsible for these illegal actions? These people are committing crimes and therefore should be held accountable by the courts. But the courts are not independent. They are not doing their job properly."
In Ms Bani Yahgoub's case, Ms Ebadi points out, not only the police but also the judges who jailed her were acting incorrectly. But the courts are protected by the government, she said, adding: "If that were not the case, these judges would have been arrested by now."
Another of her clients, the student Amir Yaghoub-Ali, 22, was jailed last week for campaigning for women's rights. The charges against him included spreading propaganda against the state. He was detained while promoting the One Million Signatures petition, which calls for an end to discrimination against Iran's women.
"We are told they were arrested because they were working against national security, but they say that about anyone," added Ms Ebadi. "I sometimes think the Iranian government is suffering from a phobia. They think everyone wishes to overthrow the government. When bus drivers protest against low wages, they are thrown in prison."
Ms Ebadi's strategy is to oblige Iranian officials to live up to their international obligations, through the law and the courts. Despite continued death threats, she keeps plugging away.
She came to London to publish an English version of a book on refugee rights in Iran. Many of Iran's one million Afghan refugees have not been given residency permits, so they cannot open bank accounts or send their children to school.
Ms Ebadi insists the issue is not the government's apparent paranoia about the spread of Western values. "The Iranian government has joined international conventions and says it recognises those human rights provisions as international values, not as Western values," she said. "So under no condition can they claim these are Western values."