A third fire has been added to the list of unexplained blazes as investigators continue interviewing suspects in two earlier cases.

Fire Chief Keith Rogers said a fire early Tuesday morning has similarities to fires Dec. 18 and 20 that investigators believe were intentionally set. The Dec. 18 fire damaged an exterior area of McRaven tour home, one of the city’s oldest structures, and the Dec. 20 fire destroyed Rusty’s Riverfront Grill, 615 Crawford St., a popular downtown restaurant open for about three years.

Firefighters said the home at 1248 Magnolia St., was fully engulfed in flames by the time they got the call around 2:30 Tuesday morning. The unoccupied home, less than a mile from McRaven and Rusty’s and all generally in the downtown area, was destroyed.

“It was burned so bad that we haven’t been able to determine if it was accidental or arson,” Rogers said. But, “It doesn’t look right to me.”

He said that the owner, Norman Price, 206 Overlook Drive, was renovating the house, but not living there.

Rusty Larsen, owner of Rusty’s, said he will reopen next month at 901 Washington St. Repair work at McRaven has already begun on the porch attached to a part of the home built in 1836.

Rogers said at least two suspects have been identified in the Rusty’s fire and they are being interviewed. The fire department is working with police investigators who will ultimately make any arrest.

Second degree arson, the burning of any building other than a school or church, is a felony crime and punishable by up to 10 years in prison.