A mother and her teenage son were displaced by a house fire in Mukwonago this morning.

According to the Mukwonago Fire Department, a passerby spotted smoke and flames coming out of the 2nd-floor window in a house at Main and Andrews street. 

The passerby then alerted the two residents of the home to the fire and they were able to escape from the first floor unharmed.

According to officials, the residents were unaware of the fire on the floor above them and there were no working smoke detectors on the second floor.

The Red Cross is now assisting the mother, her son, and the family dog.

The cause of the fire remains under investigation at this time. The Fire Chief says at this time, the fire is being treated as suspicious.