A woman walking along a major road in Northwest Washington’s Friendship Heights neighborhood Wednesday night was robbed, forced into an alley and sexually assaulted, according to D.C. police.

The incident occurred about 11 p.m. in the 5100 block of Wisconsin Avenue NW. Officer Araz Alali, a police spokesman, said a man approached the woman from behind and stuck an object in her back.

Police said the man took money and then forced her into an alley off 44th Street, where he sexually assaulted her. The victim was able to give police only a scant description of a man in his 40s or 50s wearing an olive green coat.

In July, D.C. police said a tattooed man sexually assaulted a woman nine blocks south, in the 4100 block of Wisconsin Avenue NW, in Tenleytown. That attack occurred shortly before midnight, and police said the victim was dragged behind a building.

Police have not made an arrest in either case; they said they do not yet know if the two attacks are related.

Earlier Tuesday, about 8:30 p.m., police said a woman who accepted a ride from a man in the 1500 block of Okie Street NE, in Ivy City, was taken to an unknown location. There, Alali said, the man demanded she perform a sex act, but she escaped.

Again, police said, the victim was able to only give a brief description of a man in his 40s wearing a black NorthFace jacket. He was driving a white four-door sedan, unknown make or model.