In the robberies, a group of one to six men, approach a person at or near the Red Line station on 63rd Street and take their property before leaving the scene, Chicago police said.
The first robbery happened about 3 p.m. Jan. 12 in the 6300 block of South Wentworth Avenue, police said.
Days later, a person was robbed about 1:15 p.m. in the 200 block of West 63rd Street, police said. On Feb. 12, another person was also robbed in the same location.
The men are between 18 to 25 years old, wearing black clothing and black masks, police said.
Anyone with information is asked to call Area One detectives at 312-747-8382.