German police are searching for anyone who knew a landscape gardener who may have targeted them by laying booby traps before he died.
Bernhard Graumann, 59, was found dead on Friday. Police believe he may be behind an explosive trap that killed a 64-year-old doctor on the same day.
Two other people with connections to Graumann were injured by an exploding piece of firewood in their home.
Those who think Graumann held a grudge against them should contact the police.
Bernhard Graumann, from the small town of Mehlingen in western Germany, died on the night of 1 March at his home. Police are awaiting an autopsy report.
Earlier that day, a 64-year-old doctor in the nearby town of Enkenbach-Alsenborn was killed in a deliberate explosion.
German police say the unnamed doctor was killed by a booby trap planted at the front door of the doctor's practice, which was apparently triggered when the victim picked a disguised device from the ground.
Less than 10km (6 miles) away in Otterberg, there was another explosion on Sunday morning.
Police said that a wooden log laced with explosives was placed into a wood-burning stove, exploding and injuring a mother and daughter after it was unknowingly added to the fire.
It is assumed that the suspect deliberately placed the booby-trapped log in the home of the victims.
Both victims were hospitalised, but neither are in life-threatening condition.