City police have charged an inmate at the Thunder Bay District Jail with second-degree murder.
They were notified of an assault at the jail on October 25.
A man was taken to a local hospital for treatment of life-threatening injuries.
On Wednesday, the victim died due to those injuries.
On Thursday the suspect a 31-year-old from Thunder Bay was arrested and charged.
The accused was previously charged with first-degree murder in 2022.