Commander disciplined in 'Operation Midway Blitz' response moved out of patrol leadership

Caroline Kubzansky, Chicago Tribune on Oct 1, 2026

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CHICAGO — The leader of a South Side police district who was recently disciplined in connection with the Chicago police’s response to a high-profile confrontation on the city’s southwest side during Operation Midway Blitz has been removed from his post and transferred to a non-patrol division, police announced Thursday.

Cmdr. Joseph Mark, who has overseen day-to-day policing in the Deering (9th) District since July 2024, will now lead the department’s alternate response section, according to a CPD news release. The alternate response section handles non-emergency calls. It’s also the typical landing spot for cops who have been stripped of their police powers.

Recently released public records show Mark was recently disciplined related to an internal investigation of how Chicago police handled protests that followed the shooting of U.S. citizen Marimar Martinez at the hands of U.S. Customs and Border Protection Agent Charles Exum. The punishment Mark was given appeared to be for a minor infraction.

The shooting kicked off a blockbuster federal court case that fell apart only weeks later and led to a day of chaos in Brighton Park as federal agents deployed multiple rounds of chemical munitions against furious residents.

It also led to an internal investigation of former Chief of Patrol Jon Hein, who was effectively the second-in-command of CPD at the time of the raids. Hein allegedly sent a “no units shall respond” message out across CPD’s internal communication system after a group of federal agents called 911, saying they were surrounded by a crowd of angry citizens in Brighton Park. News of the message incited furor among right-wing commentators, prompting then-Superintendent Larry Snelling to mount a full-throated defense of Hein at a news conference a few days later.

The investigation, categorized under “Operation/Personnel Violations/Failure to provide service,” was marked not sustained or otherwise unfounded, records show, and Hein was cleared of any wrongdoing.

Records show that at least two police supervisors — Mark and Lt. Jason Brown, also with the Deering District — were formally disciplined in connection with that investigation. Neither Mark nor Brown immediately responded to a request for comment.

According to police, Mark will be replaced by James Triantafillo, who was most recently a captain in the Harrison (11th) District. Triantafillo will take over a district that is currently enduring a spike in shootings and homicides: data updated through Sept. 27 show that homicides have increased by 117% from the same period in 2025, while shootings have jumped by 37%.

CPD’s Wentworth Area (Area 1), which covers the Deering District and a swath of the South and Southwest Sides, is within the only portion of the city to see an uptick in gun violence this year, as it’s remained flat or dipped further from 2025’s historic lows elsewhere in the city.

Thursday’s promotions also included a new Chief of Patrol. Andre Parham, who was most recently the deputy chief of CPD’s Harrison Area (Area 4), will supervise the Patrol division, considered the backbone of the department. The role has been vacant since June, when Hein retired.

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