An object thrown through the back window of an office at a mobile home park on Old Pearsall Road ignited a fire early Wednesday morning.

Firefighters were called to the 8600 block of Northwest Loop 410 at Old Pearsall Road at around 12:30 a.m.

Fire officials did not say what the object was, but they said the fire was quickly put out and minimal damage was done to the office.

No one was inside the office at the time of the fire. The arson unit was called to investigate.