Mark Duggan death
A horse drawn carriage carrying the body of Mark Duggan leads a cortege to the New Testament Church of God in north London.

Two members of the community reference group set up by the Independent Police Complaints Commission (IPCC) to investigate the shooting of Mark Duggan have resigned, it has been reported.

According to the Guardian, one member of the group claimed that the police watchdog is in some ways worse than the force it is investigating. He also reportedly raised concerns about the handling of key evidence at the scene of Duggan's death, claiming that the police were allowed to remove it.

The three-member group was set up to ensure people's confidence in the police investigation after Duggan was fatally shot by a Scotland Yard officer on August 4 in Tottenham, north London. The police claim that Duggan was armed at the time of the shooting.

The reference group were briefed on the investigation and had to sign confidentiality agreements.

Community activists Stafford Scott and John Noblemunn have resigned, according to the newspaper. The third member, Pastor Nims Obunge, has not resigned.

Scott reportedly claimed that a series of failures by the IPCC led him to lose faith in the investigation. He claimed that the taxi in which Duggan was travelling was taken away from the scene by the police immediately after the shooting.

He added that the IPCC commissioner in charge of the Duggan case, Rachel Cerfontyne, was unaware of this incident. Weeks later she was informed that the police had sanctioned the removal of the vehicle.

The IPCC also claimed that Duggan had shot at the police, only for ballistic tests to disprove this claim.

Scott told the newspaper: "I have been alarmed to learn that not only have the IPCC broken their own guidelines by giving out erroneous information to journalists regarding the 'shoot-out' involving Mark Duggan and police that didn't actually happen. But I have discovered that their investigation ... is flawed and in all probability tainted to a degree that means we will never be able to have faith in their final report into the killing."

Scott described the ongoing investigation as "shoddy."

"During the early stages of a complex investigation emerging evidence can be confusing and is certainly incomplete. The time to pass judgment on our investigation is when it is complete and the full evidence will be publicly tested. As the commissioner I have every confidence that this investigation is thorough, robust and independent," Cerfontyne said in a statement reacting to the latest developments.

Earlier, there was tension following the revelations on Nov. 18 that the police might have missed a chance to seize the gun Duggan had acquired. Police took extra security measures after it was revealed that the weapon may have been used in an assault reported to the police.

Early on Monday, the Scotland Yard said they have arrested a man in connection with the murder of Kelvin Easton, who was reported to be a close friend of Duggan. There have been conflicting versions about Duggan's motive behind buying a firearm.

The city of London witnessed one of the worst rioting in recent times after 29-year-old Duggan was shot dead during a covert police operation.