A constable and a suspected woman suicide bomber were killed and over 15 others injured in a powerful explosion at Ara civil court in Bhojpur, around 60km west of Patna, on Friday.

A middle-aged woman, who was critically wounded in the explosion, has been admitted to the Patna Medical College and Hospital.

The incident occurred at a time when the state has been put on high alert in the wake of intelligence inputs that militant outfits may carry out major operations in Bihar ahead of the Republic Day. The intelligence agencies have apprehended attacks by banned terrorist outfits and Maoists at public places such as railway stations, courts, bus stands and hospitals.

The blast was triggered around 11.35am when two undertrials - Lalbu Sharma and Akhilesh Upadhyay - were being taken to the court for production from the prisoners' lock-up. The blast was so powerful that the body of the woman, who was supposedly carrying the bombs, was blown into pieces. The identity of the deceased woman is yet to be ascertained.

A constable deployed on the court campus also died in the explosion, which forced the lawyers and the litigants present on the campus to run for security cover. The deceased cop was later identified as Amit Kumar, a resident of Shahpur in Bhojpur. Taking advantage of the melee, the two undertrials managed to escape from judicial custody.

Inspector-general (Patna) A.K. Ambedkar, who reached Ara after getting information, denied the report that the dead woman was a human bomb.

'The bombs suddenly went off, while being handed over by the woman to another person,' he said, adding that the entire incident was orchestrated by gangster Sharma, who is facing murder, loot and dacoity charges.

The associates of Sharma triggered a similar blast in June 1998 to set him free from the judicial custody. Bhojpur district magistrate Pankaj Kumar Pal and superintendent of police Akhtar Hussain told reporters in Ara that the blast was aimed at setting Sharma and his associates free. 'A search is being carried out on the court premises after the area being cordoned off,' Bhojpur SP Hussain said.

Sharma hails from Piro under the jurisdiction of Bhojpur. BJP MP from Ara and former Union home secretary R.K. Singh also ruled out the possibility of fidayeen (human bomb) attack. 'I don't think so. The truth will come out in the course of investigation,' he said, adding that there was no need for panic.

Coincidentally, the explosion took place when BJP president Amit Shah was in Patna to attend a party function. A series of bomb blasts was triggered at Patna's Gandhi Maidan in October 2013, when then BJP Prime Ministerial candidate Narendra Modi and other senior leaders of the party were addressing a rally.

Security was beefed up in Patna following the explosion. A team led by Patna senior superintendent of police (SSP) Jitendra Rana carried out a search operation in the Patna civil court premises, leading to suspension of five policemen for dereliction of duty.

Meanwhile, the home ministry has sought a detailed report from the state government on the incident. A senior officer posted at the chief minister's secretariat said the report would be sent to the central government soon. 'At present, the inspector-general (Patna zone) and deputy inspector-general (Shahabad range) have been asked to camp at Ara and monitor the investigation,' he added.

Additional director-general (headquarters) Gupteshwar Pandey said a special investigation team led by a deputy superintendent of police rank officer has been constituted to probe the incident. 'A forensic team from Patna has also reached Ara to assist the probe team,' he added.

A joint team of the National Investigation Agency (NIA) and Bihar Anti-Terrorism Squad (ATS) has arrived to probe the blast.