The Baltimore Sun reported Tuesday that information about eight attacks date back at least to Oct. 20, but five of the rapes occurred during the past weekend.
Some of the rapes have occurred in homes during robberies or burglaries, with a display of a knife or implication of a gun. Others have been initiated at bus stops, with the women being forced into a more secluded area, the newspaper reported.
"We think they're related. They're happening in the early morning hours, around bus stops, all within a fairly close location to one another," Anthony Guglielmi, a police spokesman, said of the bus-stop related rapes.
Police are not sure that the rapes are all connected to one or several assailants, but they are investigating links due to the crimes' similarities, Guglielmi said.
An elite Violent Crimes Impact Division has been brought in to assist with a police investigation of the crimes, Guglielmi said.
Police are conducting traffic stops to gain information, the newspaper said.