CHICAGO (CBS) — A rash of sexual assaults has been plaguing the West Pullman neighborhood for more than four months, police said Wednesday.

Calumet Area police detectives said several sexual assaults have happened in an area bounded by 115th Street on the north, the Little Calumet River on the south, Normal Avenue on the east, and Ashland Avenue on the west.

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The assaults happened between October of last year, and last month, police said.

The same man is suspected in all the cases.

The attacks have happened between 5:45 p.m. and 12:01 a.m. In each case, a man would approach the victims from behind and force them at gunpoint to accompany them to an isolated area. There, he would sexually assault them, police said.

The assailant is described as an African-American male, standing 5 feet 10 inches tall and weighing 220 pounds, with a light complexion. He wears a black mask, dark jeans, and light brown Timberland boots, police said.

In one case at 120th Street and Union Avenue last month, a young woman said she was attacked and sexually assaulted in an alley. She was taken to Roseland Community Hospital for treatment.

That case caught the attention of Riverdale police, who are looking for two suspects wanted for two sexual assaults in January. Those attacks happened one day apart. Both victims were 17 years old and the sketches of the two suspects look similar.

Police could not say Wednesday morning if the assaults mentioned in the community alert were related to the Riverdale incidents.