According to locals, the Tripoli suburb of Tajura is the target of a crackdown on rebels, with 'disappearances' increasing

The police took all the keys to Bilhaj's brother's house, including those to the tall metal gates outside, so Bilhaj clambers over a wall to get in. We follow him.

The doors of the house are broken down, the wood splintered. Bilhaj – not his real name – says the police sprayed something from an aerosol into the locks before they were shattered.

Inside, there are clothes scattered on the floor, including a blue uniform. Bilhaj's 35-year-old brother was once in the Libyan police. There are open drawers from where Bilhaj says money and four phones were taken. An ashtray has been overturned on the carpet.

Bilhaj's brother was taken at 3.30am on Wednesday after a dozen four-wheel-drives arrived in the sandy little square of the working-class neighbourhood of Tajura, on Tripoli's eastern edge, where his extended family live.

They took the former policeman along with his other brother, aged 32. Bilhaj says – but it is impossible to check – that 20 men and youths in his immediate neighbourhood were arrested. The night before, 12 men were taken and four more the night before that.

If Bilhaj's account seems credible it is because of the evidence of the raided house and the visceral sense of fear that emanates from him.

Unemployed like many in the area, he is a compact man in a red pullover, tan jeans and white flip-flops. His fear is visible in every word he says. He rattles out his words like a machine gun, his body tense as a boxer's. His eyes are red-rimmed due to lack of sleep.

What Bilhaj describes is a concerted crackdown on this neighbourhood, one of the main centres of opposition to Muammar Gaddafi's regime in Tripoli – an attempt to ensure that there are few willing to risk appearing on the streets for Friday's Libyan day of rage.

Tajura, with its population of about 100,000, is made up mainly of poor and middle-class Libyans who live in three-storey apartment blocks and houses built around little squares and alleys.

It is here that residents say gunmen in pickup trucks fired wildly into the crowd last week. It now feels like a ghost town, with shops shuttered and few people on the streets, which still bear the scars of the clashes.

We had been met on a dark corner by a group of youths keeping watch on the street. They were suspicious of the driver, who was sent away after being questioned briefly. There was evidence on the roadside of felled palm trees that had been used as barricades and anti-government graffiti, painted over with red paint.

"Fifteen of them came and kicked in the door," Bilhaj says inside the house. "They turned the house upside down. In this neighbourhood, 20 have disappeared. We don't know where they have gone.

"The people in this area feel threatened. They are scared. The government says if there are any protests in the streets here they will burn them."

We ask what his brothers did to be arrested. "They spoke out. They were targeted because they were ones who oppose the government. Tonight they will come and take more people. Our street is almost empty. The men have been taken and the families fled elsewhere."

It is quiet in the square. Bilhaj shows us the tyre tracks where the police cars swept in. Dogs bark occasionally but there are no people visible.

Bilhaj does not sleep at home but stays in different places. "I don't sleep at night. After what has happened no one wants to sleep in their houses any more. We don't know who is with us and who's against us," he says. "They know who we are. When you go in the street [to demonstrate] they take your names and photograph who's there. They call this area a terrorist area that is against Muammar. I hide in rooms outside the area."

He says the police come after 1am when the traffic has gone from the streets. That's when the young men leave as well.

We ask if he knows where the men are being taken, but he says he doesn't. "They took one man and released him for a day. Then they took him again."

He makes the same claim I have heard before of those injured being taken from the hospitals: bodies disappearing. It is impossible to verify.

"People are not even able to speak. Soon there will be no more people left calling for change of the regime."

The fear is so great now, he says, he is not sure how many people will be prepared to demonstrate on Friday. "People are afraid. Some will come out. But many are scared."

Last week anti-government protesters set out from Tajura to try to march to the district's central square but came under fire. Now, the regime has so intimidated its opponents in Tripoli that it appears to have secured the city for the time being.

The crackdown in the last few days in this district follows the deaths, according to opposition sources, of at least 17 people in Tajura.

The regime, including Gaddafi's son Saif al-Islam, has repeatedly denied that any force has been used against demonstrators.

Bilhaj tells a very different story from the impression the government wants to give of Tajura.

Two days ago when the Guardian was taken to the same suburb by the regime's minders it was met by an organised demonstration of about 150 who shouted support for Gaddafi, watched by stony-faced residents on the balconies above. Tajura is not with the regime. Whether it is still prepared to defy it remains to be seen.