Authorities are investigating a burglary at former president Donald Trump’s campaign office in Ashburn, Va., after reviewing surveillance footage showing a man inside with a backpack strapped to his chest on Sunday.

The Loudoun County Sheriff’s Office said it responded to the burglary report about 9 p.m. Sunday and that a video showed a man inside wearing a dark baseball cap with insignia and a dark hoodie. The man’s backpack appears to be partially full in the still images from the surveillance video released by the sheriff’s office.

“It is rare to have the office of any political campaign or party broken into,” Sheriff Mike Chapman said in a statement. “We are determined to identify the suspect, investigate why it happened, and determine what may have been taken as well as what may have been left behind.”

Ashburn is a Northern Virginia suburb about 30 miles from downtown Washington. The sheriff’s office said the Trump for President campaign is leasing the office.

A spokesman for the sheriff said Monday that the Trump campaign office, which also serves as the headquarters of the Virginia 10th District Republican Committee, had been cleared out while law enforcement agencies from Loudoun County and other jurisdictions canvassed the location. They asked for the public’s help identifying the suspect.

“It’s an office park area, kind of a remote office park area, so there would not have been an awful lot of people” on Sunday night, spokesman Thomas Julia said. “Once we know who this person is and the motivation, we’ll have a second statement.”

Republican Party of Virginia Chairman Rich Anderson said he knows “very little” about the incident.

“I got a phone call from my people this morning telling me that an intruder had somehow made his way in,” Anderson said. “They’ve handed it off to the Loudoun County Sheriff’s Office. It’s really in their hands, so we’re just in a wait-and-see mode.”

Anderson said he had not been briefed yet on whether anything was missing from the office.

This is a developing story and will be updated. Gregory S. Schneider and Teo Armus contributed to this report.