They demanded immediate removal of senior jail superintendent Harun-ur Rashid for assaulting prison guard Mustafizur Rahman.
The protesters called off demonstrations at around 10:00pm after Maj Hafizur Rahman Mollah, deputy inspector general of prisons in Rajshahi division, over speakerphone from Naogaon assured them of taking necessary steps.
The prison guards alleged that Harun first slapped Mustafiz for failing to control the prisoners during an event inside the jail at about 4:00pm.
He then beat him with a stick until he fell to the ground and his clothes were torn, alleged Mustafiz's colleagues, who rescued him.
About 500 prison guards staged protests at the jail demanding immediate removal and punishment for the jail super around 6:30pm after all prisoners were taken to their cells from the event.
They alleged that Harun often beats prison guards over trivial matters.
Harun however could not be contacted.
Hafizur told The Daily Star, "The situation is now under control. We shall listen to the prison guards and take proper action according to the rules.”
The headquarters of prisons yesterday formed a two-member investigation committee to probe into a demonstration by the jail guards in Rajshahi Central Jail on Saturday.
They staged the demonstration demanding removal of Senior Jail Super Harun-ur Rashid who infuriated them by assaulting one of their fellows before the jail inmates.
The agitating guards brought allegations against Harun for his torture on the male and female guards of the jail.
The committee, comprising Deputy Inspector General (DIG)-Prisons in Rajshahi division Maj Hafizur Rahman Mollah and Senior Jail Super of Bogra Abdur Razzak, will start investigation tomorrow.
The probe body was asked to submit its report within seven days suggesting tasks to avoid such revolts in future after finding out those responsible for the revolt.
Mollah told The Daily Star that, “The senior jail super definitely committed an offence by assaulting a jail guard before the prisoners, but they cannot avoid responsibility in the name of protests”.