Ludhiana, July 5 -- More than 15 years after the sensational murder of Namdhari sect follower Avtar Singh Tari, the CBI has intensified efforts to crack the long-pending case by releasing the sketch of one of the suspected assailants and announcing a reward of Rs.2 lakh for credible information. The agency on Saturday made public the sketch of a man believed to be one of the assailants involved in the daylight murder in 2011. The CBI said the identity of informants would be kept strictly confidential. Tari, 57, was gunned down on April 12, 2011, near Katani Kalan on the Chandigarh-Ludhiana road. According to the probe, two motorcycle-borne attackers armed with an AK-47 rifle opened indiscriminate fire on him, before fleeing. The case, initially investigated by Punjab Police, was handed over to the CBI on January 9, 2017, amid persistent demands for a deeper probe into the murder and its alleged links to internal tensions within the influential Namdhari sect. At the time, Punjab Police had linked Tari's murder to a possible succession struggle within the over 200-year-old Namdhari sect, as their spiritual head Satguru Jagjit Singh had no son and questions over succession had triggered internal friction. An FIR was registered at Sahnewal police station against Satguru Jagjit Singh's nephew Thakur Dalip Singh and two unidentified men on the complaint of Tari's brother-in-law, Balwant Singh. The officials had also found that Tari had survived at least two earlier attacks, with separate cases registered in Mohali, indicating that he had been under threat for years before his murder. The case gained further complexity after a series of dramatic developments in the Namdhari sect leadership. Satguru Jagjit Singh passed away in December 2012 at the age of 92. Days later, his nephew Thakur Uday Singh was installed as head of the sect at Bhaini Sahib, while his brother Dalip Singh later emerged as head of a rival faction based in Sirsa, Haryana. The sect was rocked again in April 2016, when Mata Chand Kaur, wife of Satguru Jagjit Singh, was shot dead inside the Bhaini Sahib complex. That murder is also being investigated by the CBI. In that case, Dalip Singh was declared a proclaimed offender earlier this year....