The fire broke out around 9:30 Monday night at the Frostee Freeze on Clovis and Balch.
Deputy Fire Marshall Don MacAlpine said neighbors called 911 to report heavy smoke and flames pouring out of building.
"This is the latest of a string of events we've had at that location," MacAlpine said.
When crews arrived, MacAlpine said, the fire had spread throughout the interior of the building, damaging kitchen equipment, tables and chairs and forcing the business to board up its doors and close indefinitely.
"There was significant damage," said MacAlpine. "Probably an upwards of $100,000 dollars."
Fire investigators told Action News, the fire was the fourth incident in less than a week and what makes it unusual is the fire started in the back office after hours with an employee still inside.
"Unfortunately they've been a victim of, up until last night, relatively minor vandalism including some fire events," said MacAlpine. "Last night of course went much further. There was an attempted robbery, or successful robbery, we're still looking more into that and arson."
Right now, investigators aren't saying how the suspect got inside or what he made off with, but they say it was evident he was familiar with the layout of the restaurant and knew exactly what he was after.
"The fire is still a part of the ongoing investigation, but it was enough to know the person came in there prepared to do what they were going to do," said MacAlpine.
With such widespread damage inside the structure, investigators said they're thankful no one was hurt in the fire.
If you have any information on the suspect, contact Fresno Police or Fire. You can remain anonymous.