WINDSOR – Another inmate at the Southwest Detention Centre in Windsor has overdosed.

The Ministry of Corrections has confirmed an inmate at the jail overdosed on Friday morning.

Ministry spokesperson Greg Flood tells CTV News "an inmate was found in medical distress this morning" and "the inmate has been transported to hospital."

CTV News has confirmed the unnamed inmate remains in hospital.

CTV News has also confirmed a second inmate overdosed on Thursday and has since returned to jail.

That makes four overdoses at the jail since Oct. 30, although sources believe there have been more than four overdose incidents at the Southwest Detention Centre at that time. All are believed to be connected to fentanyl use.

How the drugs entered the jail remains a mystery.

Corrections staff would not answer questions about the subject.

"We shouldn't be hearing about overdoses in jails in the first place," says Brandon Bailey of the Windsor Overdose Prevention Society. "When someone goes into jail, they are expected to go in there be safe, whether they are there for a week or a year.

The news follows the death of 31-year-old Joe Gratton.

He died from an overdose inside the jail on Oct. 30.

A second inmate overdosed at the same time. Blake Carter, 21, remains in critical condition in hospital.

A rally is being held Sunday at 1 p.m. at the Southwest Detention Centre, one of several rallies across Ontario being held by families who have lost loved ones to drugs in jails.