Relatives of Tottenham man whose death during arrest sparked London riots say questions remain over why he was fatally shot

The family of Mark Duggan, the Tottenham man whose death in a police shooting last month sparked five days of widespread riot and disorder, believe officers were operating a "shoot to kill" policy.

Duggan's brother, Shaun Hall, 42, said ahead of Duggan's funeral on Friday: "The police were clearly operating a shoot to kill policy that day. They are supposed to disable, not kill, suspects. If they hadn't shot and killed Mark there would have been no riots."

The family, in exclusive interviews with the Guardian, said they had been told that the bullet fired at Duggan's chest after officers intercepted the taxi he was travelling in, would have killed him in seven to 12 seconds, giving him no prospect of surviving.

They are devastated by his loss and distraught at the misinformation initially put out that the incident in Ferry Lane in Tottenham, north London, was a "shootout".

The Independent Police Complaints Commission (IPCC), which is investigating the killing on 4 August, confirmed the two shots that were fired were from a CO19 firearms officer.

The family say they have been told there was no forensic evidence of Duggan's fingerprints on the non-police issue gun recovered at the scene of the shooting, and they have many unanswered questions. The Guardian has established from sources outside the family that the gun was found inside a sock.

The family are also puzzled by reports that the taxi Duggan was travelling in when he was shot was initially moved from the crime scene and then returned.

"It's as though the police have messed with the whole case," claimed Hall. "Why did the police shoot to kill, why was the taxi moved from the crime scene, why were Mark's fingerprints not on the gun? We don't know whether or not that gun was planted."

Scotland Yard has refused to comment on any aspect of the operation to arrest Duggan, saying it is the subject of an IPCC inquiry.

The family are also distraught that they read about Duggan's death in the media before they received formal notification from the police about it.

The Met's new north area commander, Mak Chishty, went to his parents' home in Tottenham on Friday evening last week to apologise for the police's failure to inform them more promptly about Duggan's death. It was the family's first formal communication with a senior police officer.

"I rushed down to Ferry Lane after the shooting," said Duggan's girlfriend, Semone Wilson, 29, who had been with him since they were both 15.

She had heard rumours that he had been shot. "I was asked to come through the police tape and to give a description of Mark. They told me that the man who had been shot had tattoos and I was asked to describe Mark's tattoos."

However, the police did not confirm Duggan's identity to her at the scene.

A police spokesman said Met family liaison officers met two members of the family that night and that they had agreed with them that the family members should inform the parents of Duggan's death. The spokesman said Chishty had visited the family after hearing of their concerns and had "apologised for how this was managed".

The family went to a Tottenham mortuary on 6 August, in the presence of the IPCC, and confirmed the dead man was indeed Duggan.

Later that day, they organised a peaceful march to Tottenham police station from the Broadwater Farm estate, to protest about the shooting and state their belief that police had failed to provide information.

"I went into the police station with my mum and told the officers on the front desk that I had come to report a murder," said Wilson.

"They asked me whose murder I was reporting. When I told them it was Mark Duggan's murder they said to me, 'Don't worry, it's being sorted out,' and they told us to go and wait outside so that they could deal with other people who were reporting crimes."

They waited for four hours, being told repeatedly by police that someone would come out to speak to them. But no one did, so the family went home.

"Things were peaceful when we left," said Wilson. "When I saw the pictures of the rioting and looting on TV later in the evening I didn't realise at first that it followed on from our protest."

The family have distanced themselves from the violent disorder of that night – and in the following days – after the peaceful protest at the police station. They said they support the Guardian and London School of Economics study into the causes and consequences of the riots, announced on Monday.

Mark's mother, Pam, 53, said her son would have been opposed to the disorder that spread to cities across England. "Mark wouldn't have condoned it and we don't condone it," she said.

"You killed my son in cold blood," she said of the police's actions. "I just want the police to admit that they killed my son. Why didn't the police shoot him in the foot instead of in the chest? I'm on Valium because of what happened. All of this has made me feel as if I want to go and lie down with my son.

"One of my other sons was stopped in a car a few days after Mark was killed and questioned by police. He went out in a taxi at the weekend and I was terrified he was going to be shot dead too."

The family are also upset by media reports that Duggan was a gangster. They admit he was known to the police and had been on remand, but emphasise he had no criminal convictions.

"If Mark had been a gangster he would have lots of money, which he didn't have," said Mrs Duggan. "He would have been out all the time with lots of others but he wasn't. He was a loving boy with a good heart. He loved his children, he loved everybody. People from the whole community will be attending Mark's funeral and people will see who knew and loved Mark. Mark was the kind of person who would say if he saw someone fighting: 'Don't bother with that.'

"I lived on the Broadwater Farm estate for 26 years and I think that the police have got worse since the riots there in 1985. They're really picking on people. Mark had been harassed by the police for years."

Wilson said her three children with Duggan had been left devastated by the loss of their father.

"They were on holiday for a week with other family members when Mark was killed so we managed to keep the news from them for a week.

"But when I finally did break the news to them, the youngest one immediately vomited.

"The other day I was in the street with my 10-year-old son and saw a white man being stopped and searched by police.

"My son asked me, 'Are they going to shoot him now?' I just tried to change the subject because I didn't want him to start asking lots of questions about Mark's death."

Hall said the family were determined to get justice. "Justice for me is someone being punished for what they've done. The person who killed Mark needs to take the blame for it. Someone needs to be made accountable for what happened. We've heard everyone talking about gangs but the police are the biggest gang of all, an institutionalised gang.

"And like any other shooter in any other gang the person who killed Mark should be punished. Someone needs to be made accountable for this and we're not going to stop until we get justice."

The family are appealing for anyone who witnessed the shooting to contact Birnberg Peirce solicitors in confidence on 020 7911 0166.