Loudoun County Sheriff’s Office investigators are searching for an unidentified man who robbed an Ashburn bank Wednesday afternoon, the sheriff’s office said Friday.

Detectives released a surveillance video image of the man suspected in the robbery at the Bank of America at Ashburn Commons Plaza. Authorities hope that the public can assist in identifying and locating the man.

The bank robbery was the third in the area in recent weeks. Authorities announced Wednesday that they had arrested a former Loudoun resident accused of robbing a PNC bank in Sterling this month and a Wells Fargo bank in Herndon last month.

Authorities described the suspect in the Ashburn robbery as a white male of average build, about 5 feet 11 inches tall, who at the time of the robbery was wearing a black mask, light-colored jeans, a black jacket with a hood, and a yellow-and-green hand-knit scarf.

The man entered the Ashburn bank shortly before 3 p.m. Wednesday, implied that he had a weapon, although none was shown, and demanded cash, authorities said.

He fled on foot with an undisclosed amount of money, the sheriff's office said. Witnesses said they did not see a vehicle, and authorities said there was no indication that anyone else was involved in the holdup.

Bank robberies are rare in Loudoun — the county reported only one in 2012 and one last year — making the two that have occurred in the county this month unusual.

The suspect in the first case, Jonzel M. Bailey, 22, formerly of Sterling, was arrested in Miami and returned Jan. 18 to Fairfax County, where he remained held on charges stemming from the Dec. 27 robbery at the Herndon bank, officials said.

Bailey is also suspected of robbing a PNC Bank in Sterling shortly after 9 a.m. Jan. 2. Authorities quickly released surveillance video images from that robbery, resulting in numerous tips that helped detectives identify Bailey as the suspect, the sheriff’s office said.

“The sharing of information with neighboring jurisdictions and quickly relaying the details of the robbery to the public helped solve this case,” Loudoun Sheriff Mike Chapman said in a statement last week. “This is a prime example of how good working relationships with our partners in law enforcement and our partners in the community can help solve crime.”

Bailey was charged with robbery in Loudoun on Jan. 18.

Authorities said last week that they hoped the public could once again provide leads that will bring about an arrest.

Anyone with information about the Ashburn robber is asked to contact Detective M. Grimsley of the Loudoun sheriff’s Criminal Investigations Division at 703-777-0475. Callers wishing to remain anonymous are asked to call Loudoun Crime Solvers at 703-777-1919. If tips provided to Loudoun Crime Solvers lead to an arrest and indictment, the caller could be eligible for a reward of up to $1,000.