Ciudad Juarez - Mexican police could be involved in suspected drug cartel murders which have come to light with the discovery of at least six bodies buried near the US border, a prosecutor has said. "There is possible involvement of members of security units, both at state level and federal level," Mr Arturo Gonzalez Rascon, prosecutor for the northern state of Chihuahua, told reporters. Mexican investigators and FBI agents, using methods deployed in Kosovo to find mass graves, have extended their search at the La Campana (the Bell) ranch.