These are among the latest casualties of the spiralling violence that's engulfed the Mexican beach city of Acapulco. The four men were found tied up, each with a gunshot to the head at a car workshop. 　　Police said an unknown group burst into the office, shot the victims, then set light to two vehicles after pouring petrol over them. Flashpoints like Acapulco have seen a wave of violence, as drugs gangs battle for control of the Pacific coast. 　　The cartels have been terrorising the beach city since troops killed a senior gang kingpin two years ago,triggering an internal power struggle. Drugs violence across Mexico has claimed more than 42,000 lives in the past five years