This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.CHICAGO — A person of interest in connection to the fatal shooting of a Chicago officer was still being questioned Sunday morning, and the search for the gunman continues. Chicago police said that person is not considered a suspect in the shooting of 23-year-old Officer John Rivera, an off-duty cop, who was shot and killed after leaving a River North bar early Saturday morning. Police said it appeared to have been a random act of violence. “Each and every day we dedicate our professional lives to protect this city and fight for victims of gun violence, but today we grieve alongside the countless number of other Chicago families also torn apart by reckless acts of individuals who feel undeterred to use and carry guns in the City of Chicago,” Chicago Police Superintendent Eddie Johnson said. According to official reports, Rivera was sitting in a vehicle on the 700 block of N. Clark Street around 3:30 a.m. Saturday when two men approached and one fired shots into the car, striking Rivera in the chest, arm and mouth. Rivera was rushed to Northwestern Hospital, where he was pronounced dead at 3:50 a.m. A 23-year-old man in the vehicle with the officer was also shot and taken to the hospital in critical condition, but is expected to recover. Johnson said the investigation is still preliminary, but at this time the shooting appears to be random. “This appears to be an unprovoked attack against a group of individuals who went out to unwind on a Friday night,” Johnson said. After finishing their shift around 10 p.m., Rivera and another officer were out with a third man and a woman, police said, and were sitting in their vehicle after leaving a late-night bar and pizzeria when the shooting occurred. Johnson and Deputy Supt. Anthony Riccio said police are examining footage from a large number of cameras downtown, and have not found any evidence of a confrontation prior to the shooting. It appears the car was specifically targeted, and does not appear to have been a carjacking or robbery attempt, Johnson said. “They were seated inside of the vehicle, we know they did not have any sort of confrontations with anybody, they did not have any type of incidents that we believe would have provoked any type of shootings or confrontation,” Riccio said. Rivera had worked for the police department for just under two years in the Gresham district on the city’s South Side. Johnson noted it’s the same district he served in as both an officer and police commander, and it’s where his son currently serves as a Chicago police officer as well. He said Rivera had spent his final shift investigating a murder and consoling a family who lost a loved one. “This kid is 23 years old, his whole life and career ahead of him, and he’s gunned down senselessly,” Johnson said. “From what I know about him – he’s the kind of officer we want in Chicago. A hard worker who loved going out and solving problems.” Neighbors in the tight-knit community of Hegewisch where he lived said Rivera had been planning to be a police officer since he was just 16 years old. Neighbors said Rivera worked as a mechanic to put himself through school, studying criminology. He would stop by and chat with now-retired police sergeant John Sanchez, who lived down the street, and ask about his time as a police officer. Sanchez said he always told Rivera to watch his back – on and off the job. “Mark my words: we will find them,” Johnson said. An autopsy will be done Sunday.