AUSTIN, Texas (AP) — Surveillance video shows someone igniting an object and throwing it onto the porch of the Texas governor's mansion just before a fire that caused significant damage to the landmark building, investigators said Thursday.

State Fire Marshal Paul Maldonado said investigators were still reviewing the video, but that it did not show the arsonist leaving the mansion's front yard. Maldonado said he did not know if other people were present.

The two-story Greek Revival style house has been the official home of every Texas governor since it was completed in 1856, including Sam Houston and President Bush.