An early morning fire at a Lake Elmo residence might be a case of arson.

Keith Effertz was home when somebody threw a fire bomb through his garage window on the 5300 block of Lake Elmo Av. about 4:15 a.m. He told authorities that he heard several loud crashes and saw a vehicle speeding away.

Effertz called 911, but was able to put out the blaze before fire crews arrived.

The home sustained minor damage, the Washington County Sheriff's Office said.

The Washington County Sheriff's Office and the Minnesota State Fire Marshal are investigating.