Calcutta, July 17 :    Calcutta, July 17:  Eight days before the first anniversary of the Khadim's abduction, investigators suffered a setback when unidentified assailants shot dead a key witness in a paddy field in North 24 Parganas. Rafique Khan, 45, was hacked with sharp weapons and shot dead allegedly by his rivals outside his home in Pakuria village. The conviction of several accused in the abduction of Khadim's co-owner Partha Pratim Roy Burman depended on the testimony of the 'shady' businessman. This is the second setback for the criminal investigation department looking into the case after the death of Asif Reza Khan - the right hand of the adduction's mastermind, Aftab Ansari - last year in a police encounter at Rajkot. Rafique was the owner of the house in Pakuria village at Haroa where Roy Burman was held captive for nine days after his abduction from Tiljala on July 25 last year. Like Asif, Rafique had agreed to testify against Happy Singh and Anita who kept guard at the dingy house till August 2, the day Roy Burman was released for a large ransom. Villagers discovered the bullet-ridden body barely some yards away from a police camp and recognised the victim as Rafique, whose deserted house became a centre of attraction after the CID declared that the Khadim's boss was kept there. Special IG (CID) V.V. Thambi said a CID team has left for Haroa to investigate the circumstances under which Rafique was killed. 'The criminals have all been identified. The murder seems to be a result of a local dispute and does not appear to have any connection with the Roy Burman case,' said Thambi. However, the CID officers will find out if the attackers had any links with the Aftab Ansari gang. Several persons were questioned in connection with Rafique's killing. 'He had recognised most of the abductors and his statement in court would have been vital because Roy Burman was kept his house and he knew what was going on in the place. His death is definitely a big setback,' said a senior CID officer. However, the CID had not requested the North 24 Parganas police to provide security to Rafique. 'The CID did not even bother to inform us that he was a government approver, forget providing him security,' said a senior police official connected with the probe. Preliminary investigations reveal that Rafique had a long-standing dispute with local goons over the control of bheris. 'We have found that the people who pulled the trigger today had made a similar attempt on his life a few years ago,' said superintendent of police, North 24 Parganas, M. Hari Sen Verma.