A suspicious house fire is under investigation by the Joplin Police Department. The fire started around 5:00am this morning at a vacant house in Joplin. The Joplin Fire Department responded to the fire at 7:15 Hill Street and fire crews worked quickly to put out the fire. That wasn`t the end of that fire however. Around 8:30 this morning, crews were called out again as the fire flared back up. Fire fighters cut holes in the roof to ventilate the attic and get the fire back under control.