Detectives are looking into a series of robberies carried out by a man with a knife in the Culmore area, according to authorities.

Fairfax County police said that four robberies have been reported in the 3300 block of Glenmore Drive since Saturday, with all victims saying a man approached them with a knife and demanded either cash or property before running away.

Police described the suspect as a white man who is between 17 – 25 years old and is 5’8 and 180 pounds. The man was also said to wearing a mask, according to police.

These are the reported robbery incidents so far, per police:

• June 5 at 9:01 p.m. — The victim was approached by a man with a knife who demanded property before running away
• June 5 at 10:13 p.m. — Two victims were approached by a man with a knife who demanded property and physically assaulted a victim before running away. No injuries were reported
• June 8 at 10:37 a.m. — The victim was approached by a man with a knife who took cash and property before running away
• June 8 at 4:57 p.m. — The victim was approached by a man with a knife who demanded property and assaulted him before running away. The victim was taken to a hospital for injuries that were not life threatening

Officers are increasing foot and vehicle patrol in the area and are asking for the community to report suspicious activity.

To report suspicious activity, people should call Fairfax County police’s non-emergency line at 703-691-2131.

Anyone who is a victim of a robbery, or see a robbery in progress, should immediately call 911.