Officials say a package found contained a "large quantity" of tobacco and "shatter," the most potent form of cannabis.

On Aug. 15 a lockdown was ordered at the prison after opened contraband packaging was found within the property.

A lockdown is in place at Warkworth Institution after contraband was found on Saturday.

Since March 16, federal correctional facilities in Ontario have decreased their inmate population by nearly 2,000.

Northumberland OPP and Correctional Services of Canada investigated a reported assault on Jan. 16 at the prison.

Correctional Service Canada ordered the lockdown and search of the prison on Jan. 22.

A lockdown went into effect at 10 p.m. on Wednesday night to conduct a search of the prison.

The union representing correctional officers at Warkworth Institution claims the prison has had 566 incidents deemed "acts of aggression" so far this year.

Correctional Service Canada says Joseph Archibald, 43, died while in custody on Nov. 23.

Jeffrey Bruce Woodman died at the prison on Sept. 4, 2017, while serving a six-year sentence.