A suspect was in custody after a man was shot and critically wounded late Wednesday night in a basement apartment in Avalon Park on the South Side. Around 11:10 p.m., the man, 18, was among a group of people in the apartment in the 7900 block of South Blackstone Avenue when someone he knew opened fire, striking him in the right arm and left side of the head, Chicago police said. He was taken to the University of Chicago Medical Center where he was in critical condition, police said. A suspect was taken into custody but no charges have been announced.