Bhubaneswar: It was a blind case with no immediate material evidence and eyewitnesses. The crime branch, which took over the investigation, said Punjilal’s letter to the Balangir SP to derail the probe, forensic examination of bomb remnants, a glue, and a psychological trap led them to Punjilal.Arun Bothra, then IG (crime branch) and now ADG (railways and coastal security), who led the investigation into first such case of a gift bomb in Odisha, narrated the details of how they filtered the evidence that came their way and nailed Punjilal.“During the investigation, Punjilal once told me that he never thought we would be able to zoom in on him. Nobody was suspecting Punjilal until I delved into the case in the first week of April 2018. He was extremely cunning (shatir). The letter he sent to the SP, Balangir was a breakthrough. When I scanned through the letter, I thought in Patnagarh no one can write such a neat English letter unless one is learned. I asked the investigating officer about the suspect (then Punjilal was a routine suspect) and came to know that he was an English lecturer,” Bothra told the media after Punjilal’s conviction.Narrating further, he said Punjilal bought 10 envelopes to send the letter to the SP. The crime branch found the remaining nine envelopes in his home that matched the ones sent to the SP. Second, the forensic examination of dry glue on the used envelope and the glue case in his home matched. “The printer in which it was printed was retrieved, and the laptop used to type the letter was recovered,” Bothra recalled.What also immensely helped the crime branch secure Punjilal’s conviction is that the sleuths recovered the wrappers of the locally-made bombs that Punjilal used to gather gunpowder to make a high-impact bomb. “He used several bombs and extracted the gunpowder. We found the remnants in his backyard,” said Bothra.Punjilal hatched a plan to eliminate the entire family of Sanjkuta Sahoo, his colleague at Jyoti Vikash College, Bhainsa at Patnagarh in Balangir district, and on Feb 23, the gift bomb consignment reached Sahoo’s home. Young techie Soumya Sekhra and his grandmother died in the explosion of the gift that Punjilal couriered from Raipur. The newly-wed bride, Reema, survived the blast.