London, England (CNN) -- The officer who pushed a man that later died at last year's G-20 protests in London, England, will face disciplinary proceedings for gross misconduct, Metropolitan Police Commissioner Paul Stephenson said Tuesday.
Public prosecutors announced last week they would not file charges against the officer, who has not been named publicly.
The decision provoked outrage from the family of the victim, Ian Tomlinson. Video taken by witnesses showed the officer shoving Tomlinson shortly before his death.
That decision still left the officer open to disciplinary proceedings by the police force, the Metropolitan Police, and Stephenson said Tuesday he believed the officer was liable for gross misconduct.
"I do fully understand the Tomlinson family and the public's sense of anger, having seen the video of the incident prior to the death of Ian Tomlinson," Stephenson told the House of Commons Select Committee.
"I do understand the level of outrage that this did not lead to a criminal prosecution. I can sense, I can feel it. I've got real sympathy when a family finds itself in that position."
Stephenson said the incident had cast a shadow over the professionalism of the entire force.
"It is right and proper that we do move swiftly with those misconduct proceedings," he said.
Tomlinson died April 1, 2009, in London's financial district as demonstrations took place against the G-20 summit being held in the city. He was returning home from his job selling newspapers and had not been taking part in the protests.
Videos shot by witnesses showed a police officer apparently pushing Tomlinson to the ground. Prosecutors said he was also struck by a baton.
An initial autopsy ruled Tomlinson died of a heart attack, but a second one found he died from an abdominal hemorrhage.
The Crown Prosecution Service announced last week that for a range of reasons, the officer would face no criminal charges -- even though they found the officer's actions could have been considered an assault.