Detectives are questioning a person of interest in the fatal shooting of Cook County Associate Judge Raymond Myles early Monday outside his South Side home, a police source said.

Multiple “possible people of interest” have been identified, and investigators recovered physical evidence and surveillance camera footage from the West Chesterfield neighborhood killing scene, CPD spokesman Anthony Guglielmi said.

“Identifying people to bring in for questioning within 24 hours is exceptional in a murder case,” he said. “We’re anxious to get to formal interrogations.”

One person was in fact being questioned Tuesday evening, a source said.

Based on the time of the shooting and the number of times Myles was shot, detectives think the shooting could have happened during a robbery attempt, Guglielmi said. But nothing appeared to be taken from the 66-year-old judge, his 52-year-old girlfriend, who was shot in the leg, or the house in the 9400 block of South Forest. Police haven’t ruled out whether Myles was targeted.

“The significance of this case is important. It’s an attack against the justice system,” Guglielmi said. The FBI is offering a $25,000 reward for tips leading to an arrest.

About 4:50 a.m., Myles’ girlfriend encountered the shooter on a concrete pad between the house and the garage, Chief of Detectives Melissa Staples said on Monday. The two “exchanged words” and the woman was shot. The woman didn’t appear to know the shooter, Staples said.

Myles came out of the house in response to the noise. He and the gunman argued and the man shot Myles multiple times before running away, Staples said. His girlfriend called 911.

Cook County Associate Judge Raymond Myles | Cook County Circuit Court photo

A neighbor said he was in his home when he heard a woman outside yelling, “Don’t kill him! Don’t kill him!” Then he heard about five gunshots. The neighbor went outside and saw the girlfriend lying in the backyard. Myles’ body was on the back porch.

They were taken to Christ Medical Center in Oak Lawn, where Myles died within an hour. The woman is expected to survive.

Police sources told the Chicago Sun-Times that investigators are looking into whether the shooting was related to recent threats against Myles, or an apparent road-rage incident that left him with serious injuries last year. Police are also investigating a protection order that Myles’ girlfriend took out against a man more than a year ago, sources said.

Guglielmi said Tuesday that detectives “aren’t discounting anything.”

In September 2015, Myles was trying to park when another driver struck his car. The other motorist allegedly punched Myles in the face when the judge began taking pictures of the damage. Myles reportedly suffered a fractured nose and other injuries requiring surgery. Deandre Hudson is facing an aggravated battery charge in that case. He’s free on bond, records show.

Selected to fill a vacancy in 1999 and formally appointed as an associate judge in 2001, Myles presided over several high-profile cases. In 2008, he ordered William Balfour, the estranged brother-in-law of Oscar-winning actress Jennifer Hudson, held without bail in the slayings of her mother, brother and nephew. Balfour was later convicted. Myles also presided over pretrial hearings for the two men convicted in the Brown’s Chicken case involving seven people slain in a Palatine restaurant in 1993.