The case of a woman BMW driver who ran over and killed a peasant farmer she had accused of scratching her luxury car has taken China by storm.
There was a torrent of angry comment on the internet after the woman was found guilty of no more than a minor traffic offence and got away with a suspended sentence.
Alarmed by the public reaction, Communist Party leaders have ordered the case reopened - but have also clamped down on further debate by telling the official media to drop the subject and closing down internet chat rooms.
A small case of apparent road rage became a national obsession
The case has provided a graphic illustration not just of the extent of popular feelings about corruption and inequality but also of the internet's ability to affect the workings of a weak legal system in a country where there is no other outlet for public dissent.
It all started on the morning of 16 October last year when a tractor pulling a load of green onions scraped the side of Su Xiuwen's metallic-silver BMW in a crowded market in the northern city of Harbin.
Ms Su reportedly swore and hit out at the poor farmer and his wife who had got down from their tractor to apologise, then drove her luxury car straight into the growing crowd on the roadside, killing the farmer's wife and injuring 12 others.
Ms Su's suspended sentence for what the judge ruled was an "accidental traffic disturbance" touched off rumours that her wealthy businessman husband was related to senior provincial officials.
The "BMW case", as it has become known, occurred in a part of the country that has been plunged into unemployment by China's free market reforms and it soon struck a chord among the country's estimated 80 million internet users.
A trickle of protest turned into a national obsession, thanks first to China's dozens of internet chat rooms and later to the wider state-run news media.
One website alone, Sina.com, reported 200,000 emails on the subject, more than 90% of them saying the sentence was too light.
"This is the kind of woman who starts an argument about a tiny scratch on her HUGE expensive car that is too big for Chinese streets," said one message, signed "Doubter".
"The police should shrug off outside interference and investigate the case in a just way," said a second.
"Money and Relationships mean too much in today's world," said a third.
Last week the government responded to the continuing outcry by announcing a reopening of investigations.
Beijing resident Liang Yen says she is
glad the government is finally taking notice of public opinion.
"It is encouraging at least that we can talk about these things these days online, and the reopening of the case shows that the government is listening," she told the BBC World Service programme East Asia Today.
The internet has become the most effective way of expressing ideas and feelings in China and is now starting to influence decision-making at the top level, according to Liu Junning, a political scientist in Beijing.
It is available not just to the urban elite but increasingly to ordinary people everywhere, and the top leaders are monitoring it closely, he told BBC News Online.
And he believes the BMW case has exposed more than just the growing gap between rich and poor.
"This is about the lack of confidence of ordinary people generally in the judiciary and in the regime itself," he said.
But others warn of the dangers of "mob justice," pointing out that much of the comment in the internet chat rooms has been based merely on hearsay.
"If a court decision can be overthrown by a chatroom debate, it shows the weakness of current moves towards an independent legal system," said Li Xiguang, who lectures in international communications at Beijing's Tsinghua University .
The serious discussion of political and legal issues on the internet on China these days is beyond the imagination of Westerners, he said.
"After all, you can talk about things like that in your free press, but we don't have that," he said.
But while it is good that Chinese can go into a chatroom and express their grievances, he said, it would not be good for public opinion to become so powerful that it starts ruling the courts.