A suspect is in custody and another is at large after a retired Chicago police sergeant was shot and critically wounded Monday morning in North Center, according to the local alderperson and police radio transmissions.The former sergeant, 74, was shot twice in his left arm and grazed in his neck about 9 a.m. in the 2000 block of West Berteau Avenue, according to a preliminary police statement. He had left his vehicle when two people started shooting in his direction.He was rushed to Illinois Masonic Medical Center in critical condition, police said.The shooting unfolded as mourners began to gather on the South Side at St. Rita of Cascia Shrine Chapel for the funeral of Officer Enrique Martinez, who was killed this month in an on-duty shooting.Police radio traffic shows the victim is a retired department member whose Jeep Grand Cherokee was outfitted with Chicago Police Memorial Foundation license plates. Ald. Matt Martin (47th) said he was told the victim is former sergeant.Martin said a suspect was apprehended, and SWAT officers were “continuing to search for the second individual.” But the circumstances of the shooting remained unclear as police continued to investigate.“It’s absolutely horrific whether it’s 9 a.m. [or] 9 p.m., whether it’s North Center or anywhere else in the city,” Martin told the Sun-Times. “It’s absolutely unacceptable. And to know that it’s a time of day when so many people are walking around, not too far removed from school drop-off, day care drop-off."Police radio dispatches show the former sergeant was found suffering from his wounds near his SUV, and a responding officer applied a tourniquet before he was taken to the hospital. Tim Shepardson, co-owner of ROCKS Northcenter, said he got to the bar and grill around 9:20 a.m. and saw police vehicles “zooming” down the wrong way of the street to the scene of the shooting.Later in the day, Shepardson captured a photo of police taking a person into custody in the 4100 block of North Lincoln Avenue, steps from his establishment.“All day, there was a tension in the air with police looking around the area," he said. “Then there was this palpable sigh of relief after the first person was taken into custody.”By 5:45 p.m., officers were still gathered in the area searching for the other suspect. Ald. Martin said he was “hoping to get more answers in the coming hours about the motive.”“Most importantly,” he added, “hoping for something positive about the victim’s condition.”Check back for details on this developing story.