Authorities are investigating the cause of an early morning house fire in Grand Rapids. In a Facebook post, the Grand Rapids Professional Firefighters Local 366 said that crews were shortly after 3 a.m. Friday for a fire at the house on Bridge Street NW between Garfield and Marion avenues. When firefighters arrived, the front of the house was on fire. Firefighters searched the house and were able to put out the flames, according to the Facebook post. There were no reports of injuries. The cause of the fire remains under investigation.