Mark Duggan, whose shooting by police sparked London's riots, did not fire a shot at police officers before they killed him, the Independent Police Complaints Commission said on Tuesday.

Releasing the initial findings of ballistics tests, the police watchdog said a CO19 firearms officer fired two bullets, and that a bullet that lodged in a police radio was "consistent with being fired from a police gun".

One theory, not confirmed by the IPCC, is that the bullet became lodged in the radio from a ricochet or after passing through Duggan.

Duggan, 29, was killed last Thursday in Tottenham, north London, after armed officers stopped the minicab in which he was travelling.

The IPCC said Duggan was carrying a loaded gun, but it had no evidence that the weapon had been fired. It said tests were continuing.

The officer who fired the fatal shots has been removed from firearms duties, which is standard procedure, pending the IPCC investigation.

Officers from the Met's Operation Trident and Special Crime Directorate 11, accompanied by officers from CO19, the Met's specialist firearms command, stopped the silver Toyota Estima minicab in Ferry Lane, close to Tottenham Hale tube station, to arrest Duggan.

He was killed by a single gunshot wound to the chest, and received a second gunshot wound to his right bicep. He was pronounced dead at the scene at 6.41pm.

The IPCC's statement said the bullet lodged in the police radio was a "jacketed round". This is a police-issue bullet and is "consistent with having been fired from a [police] Heckler and Koch MP5", it said.

The non-police firearm found at the scene was a converted BBM Bruni self-loading pistol. The gun was found to have a "bulleted cartridge" in the magazine, which is being subjected to further forensic tests.

The officer whose radio was hit was taken to Homerton hospital where he was examined and discharged later that night. The minicab driver was not injured but was badly shaken by what he saw, the IPCC said. His account, as well as those of the officers, is being examined along with the forensic evidence.

The police watchdog said it was examining CCTV footage of the area, including from buses passing by at the time.

The statement said: "Our investigators will be examining recordings of radio transmissions from both police and London ambulance service, including 999 calls, with a view to tracing further witnesses. We will also be examining any intelligence and surveillance material leading up to the planning of the operation."

The IPCC commissioner Rachel Cerfontyne said: "Any concerns expressed by the wider public about a perceived lack of information from the IPCC should be considered in the context that I am only willing to share information once I have had it independently verified and once the people who are directly involved in this case – including Mr Duggan's family and community leaders – have been fully informed."

An inquest into Duggan's death was opened at north London coroner's court on Tuesday. The coroner, Andrew Walker, adjourned the hearing to 12 December and offered his sympathies to Duggan's family.

"As members of the family will know, in due course there will be an inquest touching the death of Mark Duggan and this is the first stage in that process, he said. "Of course, as well as offering our deepest sympathies, I would like to reassure members of the family that we will be working closely with Mr Duggan's family and the IPCC throughout the process."

After the hearing, the family said they were "distressed" by the rioting in the wake of his death. In a statement on their behalf, Helen Shaw, from the organisation Inquest, said: "The family want everyone to know that the disorder going on has nothing to do with finding out what has happened to Mark. They also want people to know they are deeply distressed by the disorder affecting communities across the country."