Police took four men into custody Tuesday who were suspected of taking part in an incident in which a hand grenade was thrown onto the grounds of an asylum shelter in southern Germany last month.
The four men, who were between the ages of 22 and 37 and predominately had migrant backgrounds from Eastern Europe, didn't act out of xenophobia, according to a police press release.
Housing for asylum seekers has frequently been the target of arson and hate crime in Germany in recent months, as right-wing extremists lash out at Chancellor Angela Merkel's decision to allow 1.1 million refugees and migrants into the country last year.
No one was injured in the attack on the housing facility for new arrivals in the town of Villingen-Schwenningen on the edge of the Black Forest as the device did not explode after being hurled onto the grounds.
The Federal Criminal Office said in January that this was the first case of military explosives being used to attack a refugee shelter.