A security guard at a plastics factory in the northern town of Kilkis yesterday shot dead a foreman and his boss following a workplace dispute, before turning the gun on himself, police said. Giorgos Tsakmakidis, 40, had been a guard at the factory, north of Thessaloniki, for some 10 years but had recently run into problems with 45-year-old foreman Giorgos Bekiaridis, work colleagues told officers. Witnesses said the guard’s superior had threatened to fire him on several occasions but the owner of the firm, Aristotelis Polytakis, 60, intervened. Tsakmakidis showed up at work yesterday but went home during his lunch break and returned to the factory with a shotgun. He shot Bekiaridis dead and then turned the gun on Polytakis, who had tried to approach the guard. The gunman then sped off in his car, drove three kilometers from the factory and then shot himself, police said.