Vancouver cab driver Yash says he saw a man being beaten by three others and they wouldn't stop despite the victim's pleas for help. (CBC)

Three off-duty police officers who are alleged to have assaulted and robbed a man early Wednesday in downtown Vancouver kicked and punched him while he repeatedly pleaded for help, a taxi driver who witnessed the ordeal said Thursday.

Yash, a cabbie with Vancouver Cab who drove two of the officers to the scene, said he saw the man's lips bleeding and he seemed to be badly hurt.

The cab driver's statements provide the first dramatic account of an incident that occurred about 2:30 a.m. Wednesday in the 600 block of Burrard Street.

Yash, who asked to be identified only by his first name, said he picked up two of the officers from a pub on Granville Street and took them to a location near the Hyatt Regency Vancouver hotel on Burrard, where a fight was already underway between two people.

"They jumped out of the taxi, [leaving] the door open. Then they started beating the same guy," Yash told CBC News on Thursday.

"Three people were beating one guy, and the guy was crying very loudly, 'Please help me. They are going to kill me,' " Yash said.

The three off-duty police officers belong with the West Vancouver, New Westminster and Delta police departments. They were arrested by Vancouver police early Wednesday morning after the altercation.

Early morning altercation

The man injured in the incident is a newspaper deliverer from Surrey. He was not taken to hospital but was shaken up, Yash said.

Yash said he tried to ask the officers to stop the fight but they did not listen and yelled at him.

He then called 911 and Vancouver police arrived shortly and later arrested the three men, who had not said they were police officers, Yash said.

The officers' names have not been released and no charges have been laid. Police continued to investigate the incident on Thursday.

The 38-year-old officer with New Westminster Police Service joined the force four years ago and has been suspended with pay for at least 30 days.

The member of the West Vancouver Police Department, a junior officer, has been reassigned, West Vancouver police spokesman Cpl. Fred Harding said.

"At 12 o'clock today the officer was reassigned to desk duty and that takes place effective immediately, so he's assigned to a desk as soon as he is back on duty," Harding said Thursday.

The Delta officer, a patrolman with three years of experience, remained on active duty, Delta police spokeswoman Const. Sharlene Brooks said Wednesday.

Internal reviews underway

Vancouver police are conducting a criminal investigation into the alleged assault. The three police services for which the officers worked will each also conduct an internal review of their actions. All four investigations will be conducted by police and overseen by the B.C. police complaint commissioner, according to deputy commissioner Bruce Brown.

"I know full well that many people believe that police shouldn't investigate [themselves], but that's the way it is," said Brown, referring to the provincial legislation that guides police-conduct investigations.

"Our office has full oversight power over that investigation, so we can order a further investigation, or an external investigation, or can order a public hearing if we're not satisfied of the completeness or the thoroughness of it," he said.