Five people have been killed in a shooting in northern Switzerland, which may have resulted from a family dispute, police said on Sunday.Residents heard shots in the small town of Wuerenlingen, northwest of Zurich shortly after 11 p.m. on Saturday, leading police to find five bodies in a residential neighborhood.The shooting appears to have been a "relationship crime," Aargau canton (state) police chief Michael Leupold told reporters, adding that investigators had ruled out any links to terrorism.The suspected gunman killed three people - a 57-year-old man, a 59-year-old woman and a 31-year-old man inside a house, police said. As he walked toward his car, he then shot and killed a neighbor before shooting himself.The victims in the house were the parents-in-law and brother-in-law of the suspected gunman, a 36-year-old who lived in Schwyz canton, south of Zurich, and was reportedly separated from his wife. All were Swiss.It wasn't clear whether the gunman knew the neighbor, a 45-year-old man, and the exact motive for the slayings also remains unclear.Police said the gunman used a pistol that was not an army weapon. Switzerland has a long-standing tradition of men keeping their military rifles after their compulsory military service.