Guwahati, May 21 :     Mystery shrouds the arrest and subsequent release of six persons by a team of the Assam police in Shillong today. Sources claimed one of the arrested persons was the dreaded Ulfa hitman Munna Mishra. However, the Assam police have denied this. Sources said the police team raided a house at Kenches Trace this morning. Though no one was found in the house, the police recovered two mobile phones and a number of incriminating documents. After this the police team raided the house of an Assamese person at Lower Lumpering near Laban and picked up six suspected Ulfa rebels. They were identified as Utpal Deka of Janigog in Nalbari district, who had reportedly received arms training in 1988, Rahul Sarma alias Moni Saikia of Hilloidharigaon in Dibrugarh district, Neeraj Srivastava, Manoj Kalita, Jennifer Kalita and Gayatri Kalita. The sources claimed Neeraj Srivastava was the dreaded Ulfa hitman Munna Mishra, who had been evading the police dragnet for a long time now. Mishra allegedly threatened the raiding police party with dire consequences and dropped names of top Assam police officials. When contacted, the city superintendent of police, Bhaskar Jyoti Mahanta, denied any such incident had taken place. He said the team had gone to Shillong following a tip-off about ISI presence. 'When they did not find anyone there, they decided to take a look at a house which had been raided about a year ago,'' he said. Mahanta said a 'few normal people' were found at the house who were later handed over to the Laban police station. However, a highly-placed police official in Shillong said no one was handed over to the Laban police station. 'All the persons were released by the Assam police and even the mobile sets were given back,' he said. Farmer shot Suspected Adivasi militants yesterday gunned down a 58-year-old farmer at Balabari near Sapaguri village, five km from Kokrajhar town. The victim, identified as Nibaran Brahma, was on his way to a paddy field with his 15-year-old grandson Holonga when they were fired upon by the militants.