A large police operation was underway in Germany on Sunday to find one or more shooters who killed two men the day before in the centre of the country, police said.
The bodies of the two victims, both with gunshot wounds, were found in front of a residential address in Bad Nauheim, a town north of Frankfurt, on Saturday afternoon, Giessen city police said.
The victims were a man, 59, and his 28-year-old son-in-law, both of Turkish nationality, who "had no previous dealings with the police", police and prosecutors said Sunday.
"A big force deployment" of police from uniformed, plain clothes, and special forces branches has fanned out, backed by a helicopter, to find the perpetrator or perpetrators, it said.
The search continued on Sunday in parallel with investigations.
Authorities said "a personal motive" seemed to be behind the killings, adding that "no element indicates that there would be a danger for outsiders" crossing paths with the suspect or suspects.
Bad Nauheim is 25 kilometres (15 miles) north of Frankfurt and has a population of around 33,000. It was famous for being where Elvis Presley did US military service between 1958 and 1960 and where he met his future wife, Priscilla Presley.