CHICAGO (CBS) -- Four people were wounded Monday evening in a mass shooting on Sheridan Road near Wilson Avenue in Uptown.

At 7:09 p.m., the four male victims were near the sidewalk in the 4500 block of North Sheridan Road when a vehicle pulled up and someone inside shot them all.

A 16-year-old boy, a 19-year-old man, and a 26-year-old man were each shot in the buttocks. The 19- and 26-year-old men were taken to Advocate Illinois Masonic Medical Center in serious condition, while the 16-year-old boy self-transported to Weiss Memorial Hospital in good condition.

A 31-year-old man was shot in the shoulder, and also self-transported to Weiss in good condition.

At the scene late Monday, several police officers were spotted looking at the ground and searching for evidence through shattered glass from a Chicago Transit Authority bus stop.

No one was in custody Monday evening. Area Three detectives were investigating.