Police had issued an arrest warrant for Chauvet Stiggers, 23, naming him as the prime suspect in the assaults. Stiggers also goes by several other names like Rashaun Little, Andre Harris and Deandre Harris.
The crimes happened near 79th Street between Maplewood Avenue and Pulaski Road between March 4 and March 8.
Police say the attacker raped a 17-year-old girl in the back of his van at 79th and Pulaski on March 4. Then they say on March 5 he raped a 16-year-old girl at gunpoint also in the back of his van in the same neighborhood.
Police have not yet filed charges but say at least two counts of aggravated sexual assault could be filed late Wednesday night.