Five correctional officers from the Toronto South Detention Centre are now facing charges after an inmate was allegedly assaulted back in December.

In a news release issued Friday, Toronto police said a prisoner was assaulted by six officers.

Toronto police spokesperson Meaghan Gray told CBC Toronto that the victim was treated at hospital for non-life-threatening injuries.

Investigators say five men surrendered at a police station in the city on Friday. They were all arrested and charged with aggravated assault.

As to why the officers only surrendered Friday, Gray said the victim was not interviewed until February.

A sixth man is expected to be charged at a later date, police said in the release.

Police did not offer any other details about the case.

Warren "Smokey" Thomas, president of the Ontario Public Service Employees Union (OPSEU), which represents the guards, said OPSEU had no comment about the situation "on the advice of our internal council."

The corrections officers are scheduled to appear in court on April 20.