Police said in each incident, the man plans a date, usually through a social media app, with a woman.
They meet in the South Austin neighborhood's 5600-block of West Washington Boulevard, where the man takes out a gun and sexually assaults the woman, police said.
Police said the most recent assaults happened on Wednesday around 6 p.m. and on Sunday around 10 a.m.
Other assaults happened on Dec. 30 around 1:45 p.m., Nov. 11 around 8 a.m., and Oct. 26 around 8:30 a.m.
The suspect, who is around 26 to 30 years old, was last seen wearing a black puffy jacket, a gray hooded sweatshirt, black sweatpants and a black durag.
Area Four detectives asked anyone with information to call them at 312-746-8251 or submit an anonymous tip at CPDTIP.com and use reference RD # JK162665.
Police did not immediately provide further information.
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