Two people are in custody in connection with last week's shooting in Chicago, and a 3-year-old boy injured in gunfire remains in intensive care, authorities said Monday.
The two are regarded as "persons of interest," police told CNN. The Chicago Tribune quoted police as saying no charges have been filed against the two, who are men. They say that "several people of interest" were being interviewed.
Both men, age 22, were arrested Sunday. One of them has been identified as the possible shooter and the other as one of the people "who participated in the shooting," a police report said.
The incident occurred Thursday night in Cornell Square Park, on the city's South Side.
Three-year-old Deonta Howard -- in the hospital after being shot in the head -- underwent surgery over the weekend, said Pastor Corey Brooks, a spokesman for the boy's family.
In all, 13 people were shot. None of them suffered life-threatening injuries.
The other victims include two 15-year-olds, police said. The rest were adults ages 21 to 41.
An assault-style rifle with a high-capacity magazine was used in the shooting, which appears to be gang-related, Chicago Police Superintendent Garry F. McCarthy said Friday.
Chicago has been in the spotlight the spotlight for big-city gun violence.
A January shooting death of another child, 15-year-old Hadiya Pendleton, brought national attention to the city because the band majorette had performed in Washington at events surrounding President Barack Obama's inauguration.
The FBI's annual crime report this week showed Chicago had 500 homicides in 2012, up from 431 in 2011 and more than any other American city. Chicago officials have said homicides this year are below the 2012 pace.
Chicago does not have the highest homicide rate in the United States. Flint, Mich., has one homicide for every 1,613 residents, according to the FBI data. Detroit is close behind, with one killing for every 1,832 residents.