CHAPPAQUA, N.Y. - It's still not clear what sparked a small fire Wednesday at Bill and Hillary Clinton's Westchester estate.

The New Castle Police Department says it started just before 3 p.m. and was put out in less than half an hour.

A Clinton Spokesman tweeted the fire was in a building used by the Secret Service, not in the couple's main residence.

The former President and Secretary of State were not home at the time. 

Nobody was injured.