An investigation is underway in the College Area, after a fire breaks out in a nutrition store Wednesday morning near the intersection of El Cajon Boulevard and College Avenue.

Flames damaged a second floor loft to the Healthy Nutz store.

Firefighters say they had a difficult time getting to some of the flames, because of the way the building was constructed.

One witness said that at first he didn't know what was going on.

"I saw lights from the helicopter banging, then cops banging on the door. I couldn't really smell anything. They said the place was on fire."

No one was inside at the time of the fire.

Investigators have yet to determine the cause.