The historic Texas Governor's Mansion is shown early Sunday after a fire swept through it earlier in the morning. The fire, believed to have been deliberately set, left much of the 152-year-old home charred and inflicted damage that state officials described as bordering

Austin, Texas ? Federal investigators will scour the charred remains of the Texas Governor’s Mansion today for more clues after an apparent arsonist nearly demolished the 152-year-old home for heads of state from Sam Houston to George W. Bush.

The catastrophic blaze ravaged the elegant white mansion, cratered its roof and covered its signature columns with thick soot early Sunday.

The mansion was undergoing extensive renovations, including installation of a fire sprinkler system. Gov. Rick Perry and first lady Anita Perry were living elsewhere, and the mansion’s valuable art and antiques were in storage.

The Perrys are traveling in Europe, and return Tuesday to Texas.

State authorities say they found clear evidence that the fire was set, raising questions about the alertness of the mansion’s round-the-clock security detail.

So far, there have been no arrests.

While a national response unit from the U.S. Department of Justice hits the ground today, heartbroken state preservationists are gathering their own forces, fearful the Greek Revival home will be further damaged in the criminal investigation.

“This is something we couldn’t possibly afford to lose,” said Larry Oaks, executive director of the Texas Historical Commission. “It is badly damaged, and we’ve lost a lot of original fabric. But unless there’s something I really can’t see, I would be very surprised if it’s not restorable.”

Department of Public Safety security officers at the mansion were alerted to the fire just before 2 a.m. Sunday by a tripped smoke alarm.

By the time fire trucks arrived, the blaze that apparently started by the front door had swept the house and traveled all the way into the attic. The large trees surrounding the two-story mansion in downtown Austin made it difficult for firefighters to position their equipment. It took 100 firefighters and several hours to put the fire out, department spokeswoman Dawn Clopton said.