Police in southwestern Germany are looking for suspects after someone threw a hand grenade over the fence of an asylum-seekers' home early Friday morning in the town of Villingen-Schwenningen.Regional police spokesman Thomas Kalmbach said "it was just luck" the device did not explode and nobody was harmed.Police said the grenade still contained its explosives but it was not clear whether it still had a detonator. Forensics experts are investigating.An unidentified person threw the device toward the home at 1:15 a.m., Kalmbach said.Security personnel spotted the grenade and kept residents away while police responded.A bomb squad destroyed the device in a controlled explosion on the scene at about 5 a.m. after evacuating the 20 residents from the home.Germany took in nearly 1.1 million asylum-seekers last year and there have been multiple attacks on such residences, though primarily arson attacks are on unoccupied buildings.