It happened around 3:30 a.m. in the 700 block of North Clark Street.
According to police, two off-duty police officers and another man and woman were sitting in their vehicle after leaving a downtown nightclub. That's when two unknown men approached them a vehicle, one of them displaying a handgun, and fired multiple shots into the vehicle before running off.
The off-duty officer, 23-year-old John P. Rivera, was shot in the chest, arm, and mouth, police said. He was pronounced dead at Northwestern Memorial Hospital.
The other victim, also 23, suffered wounds to his chest and arm and was also taken to Northwestern in critical condition.
Chicago Police Superintendent Eddie Johnson said in a press conference today that preliminary information indicates this was a random act.
"This appears to be an unprovoked attack against a group of individuals that went to unwind on a Friday night," Johnson said.
Officer Rivera had served for about two years and worked at the 6th district. That's where Johnson's son continues to serve.
"He's (Rivera) the kind of officer that we want in Chicago," Johnson said. "A hard worker who loved going out on patrol and solving problems."
Police said the shooter is still at large and believe this was a random attack. Police have another person of interest in custody. They said there was no confrontation and no known motive at this time.
Johnson said police are looking at surveillance video in the area.
"Mark my words, we will find them," Johnson said.
First responders held a procession to escort the officer's body as it was transported from the hospital to the officer of the Cook County Medical Examiner.
Rivera's autopsy is scheduled for Sunday.
* Follow us on YouTube
* More local news
* Send us a news tip
* Download the abc7NY app for breaking news alerts