Patna, Sept. 23: Government Railway Police have filed a petition in the court of judicial magistrate to conduct a polygraph test on Chhathu Sahni, the prime suspect in the murder of Pritam Bhattacharjee.

Katihar superintendent of rail police Sukan Paswan said a petition was filed in the court of the chief judicial magistrate to seek permission for conducting a polygraph test on Chhathu. “The directive of the court is awaited.”

Sahni is lodged in Khagaria divisional jail. He was arrested from his native village in Naugachia police district on August 8 and subsequently produced in court, which remanded him in judicial custody.

Paswan said the decision to conduct the polygraph test was taken after efforts to elicit more information from Chhathu proved futile.

“He is a hard nut to crack,” Paswan said, adding that call details of the mobile phones of some of his associates were obtained and subsequently analysed but that did not help much.

The investigators were hopeful of cracking the blind case after apprehending Chhathu, a professional thief. Sources in the GRP said the police officers interrogated Chhathu in jail several times.

Pritam, a student from Silchar went missing from Naugachia railway station while travelling from Guwahati to Delhi by Awadh Assam Express on July 9, 2012.

His body was found six days later.

Police believe Pritam was kidnapped from Naugachia and kept on sedatives and apprehended that he may have died of an overdose.