A police investigation into the slaying of Chicago Judge Raymond Myles has produced no arrests yet, but police are questioning a person of interest, and say they are making “considerable progress” in the case.

“Teams have collected and prioritized the processing of physical evidence and have reviewed surveillance video from the neighborhood,” Chicago police spokesman Anthony Guglielmi said in an e-mail to the Chicago Tribune. “We are currently working in collaboration with the Cook County state’s attorney’s office to begin to identify potential persons of interest to question.”

The FBI has offered a $25,000 reward for information leading to the arrest of the killer.

Myles, 66, was killed early Monday when an assailant fatally wounded him and shot a woman who was with him in the leg. The judge died later at a nearby hospital. The woman, identified as his girlfriend, was also hospitalized but was expected to survive. Police say the incident appears to be a robbery, but no possessions appeared to be taken from either of the victims.

The judge was going to exercise with his girlfriend just before 5 a.m. Monday, police say. But as she left the home on Chicago’s south side, an attacker held her at gunpoint, shooting her in the leg. Hearing the commotion, Myles rushed to her aid and confronted the suspect but was shot several times.

Authorities said they were examining surveillance camera footage in the neighborhood and have “multiple and promising leads” Chicago Chief of Detectives Melissa Staples.

Myles joined the Cook County Circuit Court in 1999 when the Illinois Supreme Court appointed him to fill a vacancy. He has been with the criminal division of the court since 2009. There has been no indication that he was targeted over his duties as a judge. He was attacked in a 2015 road rage incident in which he was involved in a minor collision. When Myles took pictures of the damage, the other driver began punching him in the face. That suspect is awaiting trial on aggravated battery charges.

Police have not determined if that case is in any way related to the killing.