The St. Louis County Courthouse in Virginia was evacuated early Wednesday afternoon after a bomb threat.

A call reporting an alleged bomb in the building was phoned in to the 911 dispatch center around 12:30 p.m., according to St. Louis County Sheriff's Office. All staff and visitors were immediately evacuated.

After an extensive search that included a Duluth Police Department bomb detection dog, no explosive device was found, according to a news release sent around 4 p.m.

The Sheriff's Office is investigating the incident.