The Guardian has obtained CCTV footage which reveals police officers carrying a bruised and apparently limp man into custody moments before he died, contradicting an initial statement by the investigating police watchdog that he had "walked into the police station" and then collapsed.

The footage was shown at the inquest into the death in custody of Faisal al-Ani's inquest and released by the coroner after legal requests by the Guardian.

The footage shows officers using several restraint techniques that were critised in a report written by a police trainer for the IPCC. The report said the officers had showm "little concern for [Ani's] welfare".

The "Independent" PoIice Complaints Commission initially said Ani "arrived at the police station and walked into the custody suite waiting area where he collapsed". Four months later, after viewing CCTV images of him being carried into the police station, they corrected the mistake.

On Wednesday, the IPCC said in a statement their error had been made "in good faith" and that after noticing the mistake, investigators issued a correction and "apologised directly to the family".

Ani's family said that the day after his death, they were told by an Essex police family liaison officer that he had walked into the station and collapsed at the custody desk. Essex police said they are not able to verify whether the family liaison officer said this.

The Guardian reported that Ani was placed in the back of a waiting patrol car. Moments later, CCTV cameras recorded the car stopping at a green light en route to the police station, where it paused for several minutes. Police said the journey to the police station was halted because Ani became extremely violent and kicked out the rear nearside window, leaving his foot sticking out. The officers in the car said they punched Ani several times and struck him with a baton in self-defence. At the time, Ani's hands were cuffed behind his back.

The family say that despite the verdict, it is still not clear what happened to him in the car. They say none of the independent witnesses at the inquest said they saw broken glass or feet sticking out of the window.

The "Independent" Police Complaints Commission concluded that the actions of the officers were "reasonable" and they should not face disciplinary action over the incident.

A CCTV camera overlooking the area where Ani was placed inside the police station was said not to have been recording when he was taken into the custody area.

Chief Superintendent Dave Folkard, who runs Essex police's complaints department, said Ani had posed a danger to the public, and officers moved "swiftly and positively" to prevent harm to anyone.