Bridgeport fire officials are investigating the cause of a fast-moving fire Thursday night that left three families homeless and the landlord with serious burns.

Firefighters say when they arrived at the Salem Street home around 11:30 p.m. the upper two floors were fully engulfed in flames. One resident says when the landlord alerted him about the blaze, the man?s clothes were on fire. The landlord is being treated at Bridgeport Hospital's Burn Center.

Firefighters say it took several hours to get the fire under control. Eleven residents, including several children, were able to make it out safely. One resident jumped from the third floor to escape the flames. The Mid-Fairfield County Chapter of the American Red Cross has set up temporary housing for the families.

The apartment building next door to the house was also affected. The heat was so intense it cracked several of the windows.