Western Mexico's plague of violence continued on Christmas Day with the discovery of six decapitated heads in one state and the slaying of seven people in another. The Michoacan state prosecutor's office says, the six heads were found near the state of Jalisco in a region that has been a battleground between competing drug gangs in recent years. <br/> '<br/>Meanwhile, state security officials in the neighboring state of Guerrero says, gunmen entered a house and shot to death seven people. Guerrero is one of the states most plagued by drug gang violence. <br/>