When a small group of supporters gathered outside the court where this week the Angolan journalist and human rights activist Rafael Marques went on trial, they were arrested.
A woman was beaten up - this is the price Angolans pay for dissent.
Mr Marques might pay a far higher price for criticising seven army generals, whom he has accused of complicity in killings, torture and corruption in Angola's diamond fields.
They, in turn, have accused him of criminal defamation and are suing him for $1.2m (£800,000).
If found guilty, Mr Marques could go to prison for nine years.
For the generals, $1.2m is peanuts. They are part of Angola's tiny elite, which revolves around the 72-year-old president, Jose Eduardo dos Santos, and which has become rich on the country's oil and diamond wealth.
Since four decades of conflict ended in 2002, Angola's economy has skyrocketed, albeit from a low base.
According to the auditors Ernst and Young, it was the world's fastest growing economy from 2000-10.
But wealth and power have stayed largely in the hands of a very few families, who come closer that anything else I have seen on the continent to an African nobility.
The book that has landed Mr Marques in so much trouble, Blood Diamonds: Corruption and Torture in Angola, alleges the army and private security companies have been involved in burying miners alive, executing them en masse, and forcing them to leap to their deaths from speeding vehicles.
Mr Marques says the miners were made to jump off at intervals "so as to scatter the evidence of their deaths".
The generals deny these allegations.
Blood Diamonds shows how blurred the lines are between business, politics and violence.
It alleges members of the president's inner circle occupy several positions at once, serving simultaneously as top officials in the military, shareholders in diamond mining companies, and co-owners of the private security firms hired by the mining companies to secure the diamond fields.
The Angolan elite lives in a world almost entirely disconnected from the rest of the country's population of 20 million.
Its playground is the Ilha, a stretch of sand that curves out from Luanda, dotted with luxury villas, beachside restaurants and glitzy nightclubs.
The rich and the beautiful sip $60 cocktails, as gleaming Porsches purr past, the wrists of their drivers heavy with Rolex watches.
Prices are astronomical. It is as if they have been set deliberately high to enable people to show off just how wealthy they are.
Why else would a supermarket charge $100 for a watermelon, $200 for a chicken?
Looking out at Luanda from the Ilha, it is hard to believe this is the capital of a country that a little more than 10 years ago was fighting a vicious civil war.
Shiny white super-yachts luxuriate in the blue of the sea.
A swarm of new skyscrapers lines the horizon. One of the multi-million-dollar penthouse apartments has a helicopter landing pad.
It is here one starts to hear whispers of the name "Isabel": "This nightclub belongs to Isabel," "This is Isabel's restaurant," "That business is Isabel's, so is that one, that one, and that one."
Isabel is the eldest daughter of President Dos Santos.
President Dos Santos has developed remarkable cunning in playing off one foreign power against the other, just like he does in domestic politics
Worth an estimated $3.4bn, she has been described by Forbes magazine as Africa's richest woman.
Meanwhile, an estimated 70% of Angola's population survives on less than $2 a day - 90% of Luanda's population lives in slums.
A great deal of energy is spent trying to remove the poor from the sight of Angola's hyper-rich. Their shacks are bulldozed regularly.
The Chinese have built for them a new satellite city called Zango, dozens of kilometres from Luanda.
Its multicoloured tower blocks rise up from the scrubland, as if it had been dropped from outer space.
It is the urban poor that most worries the Angolan elite.
The security forces have moved swiftly to crush a growing number of small anti-government protests.
I met slum-dweller Mbanza Hamza, who has chosen to stand up to the authorities.
He has a large dent in his skull to show for it.
"Men came in the night and beat me with clubs," he says. "They wore plain clothes but I know who sent them."
Dealing with resistance
Money is the most effective tool for dealing with resistance. The government makes sure local beer stays cheap - it costs less than $1 a bottle.
It sponsors football clubs and pop concerts, and encourages churches; anything to distract the poor.
Free drinks and T-shirts were enough to make sure that, on the eve of an opposition protest, a huge "pro-government" march was held.
Source: Mary Harper / BBC