Bonn (dpa / lnw) - Four people were slightly injured in an apartment fire in Bonn. A granny flat was fully engulfed in flames on Thursday night, a police spokesman in Bonn said early in the morning. The four injured suffered smoke inhalation. A total of nine residents were treated on site. The police estimated the property damage at 150,000 euros. The cause of the fire was initially unclear and is now to be determined by the criminal police.