Darbhanga senior superintendent of police (SSP) Ajit Kumar Satyarthi said on Friday they had collected sufficient evidence to nail Baheri block pramukh and JDU leader Munni Devi in the murder case of two engineers in Darbhanga on December 26.

Munni is the sister of gangster Santosh Jha, whose gang committed the crime. Her relative Pintu Laldeo has already been booked in the case. Though a police team had quizzed Munni soon after the incident, legal proceedings could not be initiated against her for lack of evidence.

An investigating officer said footage from the closed-circuit television cameras obtained from Gaya Central Jail, where Santosh is lodged, had shown that Munni visited him before the incident.

Munni had, however, refuted the charges. "I am being targeted out of political vendetta. I am a people's representative and have nothing to do with such criminal activities," she said, adding that her husband had surrendered before the police to join the mainstream.

Sources said Rishi Jha, arrested from his in-laws' house at Janar under the jurisdiction of Runnisaidpur police station in Sitamarhi district, had tipped off about the gang headed by former Maoist-turned-criminal Santosh. Rishi, a native of Hasaur village in Sitamarhi district, is a close associate of Santosh.

During interrogation, Rishi revealed that he and his brother Lankesh worked for the Santosh Jha gang. Chhote Thakur had helped two sharp shooters - Vikas Jha and Pintu Jha - to escape from judicial custody in Sitamarhi about three years ago.

Rishi also told interrogators that Mukesh Pathak and Vikas Jha used to stay at Munni's house at Shivram, around 32km east of Darbhanga. He also confessed to his involvement in the killing of the two employees of a private construction company in Gopalganj in 2012 apart from the murder of former mukhiya of East Champaran district Chunnu Thakur in Muzaffarpur.

A special investigation team headed by superintendent of police (SP), special task force (STF), Shivdeep Lande, had so far nabbed nine people in the case. While Rishi, Chhote Thakur and Sumit Mishra were arrested from Sitamarhi, Tunna Jha, Anchal Jha and Om Prakash Singh were caught from Sheohar. Two other members, Subodh Dubey and Mankeshar Tiwary were picked from Bettiah in West Champaran. Pintu, the brother of Munni's husband, Sanjay Laldeo, was arrested from Darbhanga soon after the incident. The Darbhanga SSP, however, confirmed only five arrests.

However, the two main shooters - Mukesh Pathak and Vikas Jha - whose names figured in the FIR, are still at large. Police suspect that they might have slipped into Nepal to dodge the police. A source said raids were conducted in Janakpur and Kathmandu in Nepal to nab the duo.

Sheohar sub-divisional police officer Pritish Kumar said a joint team of the STF and Sheohar police had conducted a raid on Santosh's ancestral house at Dostian village under the jurisdiction of Purnahia police station on Friday morning. A cellphone belonging to Santosh's father Chandra Shekhar Jha was seized.

Three additional police camps have been set up at Jarso, Gangdah Shivram and Arga in Darbhanga district to keep vigil on alleged extortionists threatening employees of firms engaged in development work.