A Pakistani judge, Shehryar Bokhar, who was critically wounded during a police operation to end a prison uprising in the province of Punjab last week, has died in hospital in Lahore.
Three other judges were killed in the incident in the town of Sialkot on Friday, which began after they were taken hostage by inmates.
The judges had been inspecting the prison.
The chief of police in the city of Gujranwala and his deputy in Sialkot have been suspended following criticism of the operation.
Three prison officials have also been arrested.
Lawyers' groups accuse the police of acting hastily, prompting a shoot-out with the hostage-takers.
A committee of inquiry is expected to report on the incident to the government in Punjab by the end of this week.