Chief Jamie Graham of the Victoria Police Department says the allegation of a police assault on a prisoner is troubling. (CBC)

The Vancouver Police Department was called into investigate after a 28-year police veteran in Victoria allegedly assaulted a man in custody.

A 33-year-old man was taken to hospital with facial injuries Jan. 15 after an incident in the jail at Victoria police headquarters.

"We had a prisoner in the cells who was arrested for violating court conditions," Sgt. Grant Hamilton told a Victoria news conference Monday.

'This is an anomaly.'— Jamie Graham, Victoria police chief

"While in cells, there was an incident between the jail supervisor and that prisoner. The prisoner was injured and transferred to hospital for medical treatment."

Based on preliminary findings, Chief Jamie Graham suspended the officer with pay, pending further review, Hamilton said. Police have not identified the officer, a sergeant, or the prisoner involved.

Graham told reporters the alleged incident was troubling.

"However … anywhere from 5,000 to 7,000 inmates a year come to our cellblocks," Graham said. "We have very few incidents. This is an anomaly."

Video-surveillance equipment was operating at the time of the alleged assault, Hamilton said. "There is a video of the incident that will be reviewed by the investigators. Once they're done, the information will be forwarded to the Crown."

Graham asked Vancouver police to investigate and also informed the Office of the Police Complaint Commissioner, Hamilton said.