Eight prisoners, led by Siwan gangster Rajkishore Chaudhary escaped after triggering three explosions during lunchtime at the Chapra District Jail in Bihar on Monday.
Dudnath Sharma, a warder, and two prisoners were hurt in the blasts, District Magistrate Baidyanath Mishra said.
Earlier reports quoting Jail Superintendent Ramchandra Jaiswal had put the number of escapees at 13.
The escapees hurled the bombs at 1430 IST and as other prisoners scurried for cover, they used a bamboo ladder to scale the northern wall of the jail, which overlooked a road.
Mishra said he was not certain if a vehicle was waiting for them or whether they mingled with the crowd that collected outside after hearing the explosions.
He said a two-member panel had been directed to probe the incident.
The district magistrate said he had written several letters to the government to shift Chaudhary, who had dozens of cases of murder, dacoity and abduction pending against him, and some of his men to a high-security prison, but no clearance could be obtained.
He said he suspected that the bombs were smuggled into the jail by visitors who met Chaudhary in the morning.
The official also did not rule out the possibility of involvement of some of the jail staff.
Superintendent of Police Shahrukh Majid said he had constituted eight teams to track down the escapees. "Raids are on and we expect to apprehend all escapees soon."
He also said one person was taken into custody for interrogation, but refused to disclose his identity.
Bihar Minister of State for Jails Ashok Chaudhary said in Patna that Inspector General of Prisons Ravikant had left for Chapra to hold an inquiry. "Any jail staff found guilty of conniving with the escapees will not be spared."
On February 13, gunmen had opened fire and exploded bombs in the Danapur Sub-Jail near Patna to facilitate the escape of four criminals.
On March 30, 2002, six prisoners were killed and as many injured in a commando operation at the Chapra jail to break a three-day siege in protest against the proposed shifting of some inmates to Bhagalpur and Buxar jails.
The prisoners had seized control of the administration after forcibly evicting the officials.
