Bernhard Graumann, 59, was found dead from unknown causes at his home in Mehlingen in western Germany on Friday. Earlier that day, a 64-year-old doctor was killed by an explosion that appeared to come from a booby trap laid outside his practice in Enkenbach-Alsenborn, local police said in a statement. The doctor, who has not yet been named, is thought to have triggered the explosive when he bent down to pick it up, police said. Two days later, a mother and daughter were injured when a log that appeared to have been tampered with exploded in a wood-burning stove in Otterberg, less than six miles away. The younger woman, who has not been named, remains in hospital — her condition is not thought to be critical.Western Palatinate Police have linked both cases to Graumann, who is said to have had a “bad relationship” with the victims, having been involved in disputes with them in the past. The gardener’s death is currently under investigation, pending the results of an autopsy.When officers searched Graumann’s home they discovered gunpowder and “other items subject to the weapons law and the Explosives Act,” police statements said.Police also took the unusual step of warning other members of the public who may previously have fallen out with Graumann — whether in a personal or business capacity — to be on their guard. “The police cannot rule out that prior to his death, the deceased had made preparations that could endanger other people’s life and limbs,” a statement said. “In particular, people who have had a problematic private or business relationship with Graumann are urged to contact the police immediately.”A phone line set up for concerned members of the public has received dozens of calls, according to the force.