Police found six decapitated bodies alongside their heads in a van in western Mexico, one week after six others were found in the same town, the Michoacan state prosecutor said Friday. The western state is a flashpoint in a wave of violence between vicious drug gangs that has left more than 15,000 dead in the past three years. The six bodies and their heads were found inside an abandoned van in a public square in the town of Apatzingan, state prosecutor Jesus Montejano told journalists here. Warning messages were written on their backs, he added. Gruesome gangland-style killings have spiraled in recent years in parts of Mexico, amid a nationwide crackdown on organized crime involving some 50,000 troops. Gunmen opened fire on a party packed with teenagers last weekend, killing 16 people in a particularly extreme attack in country's most violent, northern border city of Ciudad Juarez. 