Chicago police were investigating a string of CTA-related stabbings that left one man dead and three others wounded over the last few days.
In the most recent attack, a 34-year-old man was riding a Red Line train in the first block of West 69th Street around 2:50 a.m. Sunday when another man stabbed him in the chest during an argument, police said.
He was taken to the University of Chicago Medical Center where he was in serious condition, officials said.
Roughly 24 hours earlier, a 37-year-old man was at the Clark and Lake station at 124 W. Lake St. when he was stabbed by someone around 2:30 a.m. Saturday, authorities said.
The still-unidentified 37-year-old suffered wounds to the chest and abdomen and was taken to Northwestern Memorial Hospital, where he was pronounced dead, police said.
On Jan. 5, a man and woman were found stabbed at a Red Line station in the first block of West 69th Street after a fight, officials said.
The 24-year-old man and a 37-year-old woman were fighting with a person they did not know who pulled a sharp object and stabbed them with it around 10:55 p.m., police said. Both were hospitalized in fair condition.
No one was reported in custody in any of the attacks.