MELBOURNE Sunday, —Police have identified the murder weapon used in the killing of two Shepparton teenagers Abina Madill and Garry Heywood as being an American .22 calibre Mossberg automatic rifle. Detective Inspector F. Holland, chief of Melbourne's Homicide Squad, said yesterday that a search for the weapon began this week. He requested anyone knowing the whereabouts of any Mossberg rifle to contact the police. He said detectives were interested in information about 350K, 351K, 352K or the 352C models of the rifle. "The 352K has a black plastic foregrip, which can be folded when not in use. It resembles a front-hand grip of an automatic rifle," he said. The "K" models might or might not have another letter after the "K". "The 350K is the same as the 352K except the barrel is five inches longer and there is no plastic foregrip. "The 351K has a different type of magazine — a tube through the butt. "The 352C is the same size as the 352K, but does not have the plastic fore grip and the magazine is a tube through the butt." To date this is the best lead since the couple was killed on February 10. Homicide detectives have remained in the Shepparton area since their bodies were found 16 days after the murder. It is believed that Abina, 16, and Garry, 18, left a dance in Shepparton in Garry's car and went to a lovers' lane about one mile away. Their bodies were later found in a paddock 21 miles from Shepparton. The day after they disappeared Garry's car was found in Shepparton. Police are hunting for two killers.