Charges have been stayed against a man who suffered broken ribs and a collapsed lung at the hands of Calgary police officers during an arrest last month.

"It's not very common for the Crown to withdraw charges, especially when there's allegations against the arresting officers, because one would read into that that perhaps the actions of the police officers are highly questionable," said senior defence lawyer Adriano Iovinelli.

"Perhaps there's serious evidence regarding those police officers and their actions."

The 34-year-old, who CBC News has chosen not to name to preserve his privacy, was originally charged with resisting arrest and possessing marijuana.

But in a letter to the clerk of the court dated Aug. 29, Calgary's Chief Crown prosecutor, Sue Kendall, stayed both charges.

"There was not a reasonable likelihood of conviction nor was it in the public interest to proceed with his charges," Kendall told CBC News.

Four police officers are currently under investigation by the Alberta Serious Incident Response Team (ASIRT) after video from a police cruiser surfaced of a violent arrest that did not match the notes arresting officers had taken, according to CBC sources.

Two Calgary officers have since been suspended with pay and two are on desk duty following the incident.

The officers' notes do not match what's seen on the video, according to sources who say the officers are facing not only assault charges but obstruction of justice charges.

The man was immobilized and unable to fight back when he was injured by officers on July 30, according to sources.

Kendall's letter was also sent to Jim Stewart, a Crown lawyer who works in specialized prosecutions in Edmonton, a Calgary police officer and the man who was arrested.

According to ASIRT, which is conducting the probe into the actions of police, the incident occurred around 9 p.m. when an officer attempted a traffic stop on a white SUV in a parking lot.

The driver ran from the truck and police chased him down. During that arrest, which was caught on a police dashcam, the man suffered his injuries.

It was the footage that kickstarted the ASIRT investigation. Police did not know the video existed until several weeks later, according to Deputy Chief Paul Cook.