Authorities in Chicago said Wednesday a 37-year-old man has been charged in the killing of a judge who handled criminal cases.

Police spokesman Anthony Guglielmi said in a tweet that Joshua Smith was charged in the shooting death of Associate Cook County Circuit Judge Raymond Myles earlier this week.

BREAKING: Chicago Police have charged 37 year Joshua Smith in connection with the murder of Judge Raymond Myles. Press conf @ 530 at CPD HQ pic.twitter.com/fBzxWa2kQI — Anthony Guglielmi (@AJGuglielmi) April 12, 2017

At a press briefing, police said robbery was the motive behind the killing and that it was "not random."

Chicago Chief of Detectives Melissa Staples said it was a targeted robbery by Smith, who she says didn't act alone. Staples said the gun used in the shooting of Myles was also used in an armed robbery in January during which the victim was wounded.

Smith was convicted of armed robbery in 2003 and served six years in prison, according to Staples.

Video cameras on Myles' home and others in the area helped police identify the car used by the suspects in the shooting and its license plate, Staples said. When police found the vehicle, it had a different license plate than the one seen in the videos, she said.

Earlier on Wednesday, Guglielmi said investigators were "questioning individuals" in the case who were "people of interest," but declined to specify how many.

Myles was shot to death Monday outside his home on Chicago's South Side. A woman he knew also was shot and wounded.

Myles had been involved in several high-profile cases, such as the murder of relatives of singer and actress Jennifer Hudson in 2008, when he ordered William Balfour to be held without bond.

Myles was attacked in 2015 after a minor traffic collision after taking pictures of the damage on his car, according to the Chicago Tribune. The other driver punched him in the face, causing serious injuries, according to court records cited in the newspaper.

The FBI is offering a $25,000 reward in the case.

The Associated Press contributed to this report.