At 2:58 a.m., someone reported two men fighting on the 3500 block of North Halsted Street, near Halsted and Cornelia.
The caller said the men were last seen walking southbound from that location.
Before police could respond to Halsted and Cornelia, a second 911 caller stated a group of men were randomly attacking people at Halsted and Newport.
One of the attackers knocked a phone out of man’s hand, said the caller.
When police arrived at Halsted and Cornelia, they found a robbery victim.
Several male blacks in their teens or early 20s, attacked the man and stole his camera, said police.
Investigators said the offenders were dressed in all black clothing.
At 3:33 a.m., an officer at Halsted and Cornelia asked for a reference number for a 0460.
A 0460 is the police code for a simple battery.
The officer said someone at Halsted and Cornelia was being arrested, but he did not give any specifics.