JACKSONVILLE, Fla. -

The Jacksonville Sheriff's Office concluded an investigation into a suspicious vehicle at the federal courthouse early Friday morning.

Investigators said a security guard spotted a vehicle backing into the loading dock at the federal courthouse and contacted police shortly before midnight.

"A very alert security guard did what we ask people to do. He contacted police. He knew it was suspicious and out of the ordinary," said Melissa Bujeda with the Jacksonville Sheriff's Office.

There was nothing of concern spotted in the vehicle, according to JSO.

"At this time, it seems the person was just trying to find a parking spot and that's where they chose to park," said Bujeda.

There were several road closures surrounding the federal courthouse during the investigation.  

"Whenever they have an initial call such as a suspicious item, our bomb squad is very educated to be able to evaluate how big of a perimeter needs to be set. Sometimes we start small and go big and sometimes we start big and go smaller," said Bujeda.

The roads reopened around 5:45 a.m.