Investigators are trying to figure out what started a fire at The Avondale Apartments near 71st Street and Riverside. 

Firefighters responded to a fire at the Avondale Apartments around midnight Monday.

Although they are still investigating the cause, officials are looking at this as a suspicious fire because of where it started. 

The District Chief with the Tulsa Fire Department, John Steiner, says "When they made access, they found the fire originated in the stairwell, which makes it suspicious in our industry. There is no reason  for a fire to originate in that location."

Firefighters say the heat of the flames may have impacted about six units, but they have minor damage. 

They do not believe anyone will be displaced from this fire.