The shooting of Marimar Martinez by a Border Patrol agent last fall is now being investigated by a Chicago Police Department unit staffed with deeply experienced detectives who will look to bring a case to Cook County prosecutors, the Chicago Sun-Times has learned.Any charging decision involving a f elony would still fall to the office of Cook County State’s Attorney Eileen O’Neill Burke. And potential roadblocks remain if the federal government refuses to cooperate with the police investigation.But it’s a notable step forward in the latest effort to hold federal agents accountable, nearly a year after the Trump administration’s aggressive Operation Midway Blitz deportation campaign hit Chicago.Martinez participated in a “mass filing” of police reports Aug. 10 at Area 3 police headquarters in North Center, along with others who showed up to report alleged crimes by federal agents during Midway Blitz.Martinez also delivered a USB drive of evidence to officers, according to a police report obtained by the Chicago Sun-Times. She was joined that day by her attorney, Christopher Parente, a former federal prosecutor. Related Marimar Martinez, shot by Border Patrol in Chicago, speaks out after Good, Pretti deaths: ‘I am their voice’ Now, the investigation into Martinez’s Oct. 4 shooting by Border Patrol agent Charles Exum has been assigned to the police department’s Investigative Response Team, according to a source with knowledge of the investigation.The detectives there “jointly have more than five hundred years of law enforcement experience, making them some of the most talented and experienced investigators the Chicago Police Department has to offer,” according to the department’s most recent annual report.No federal agent has been charged with an on-duty crime connected to Midway Blitz. Burke’s office has said “no one is above the law — including federal agents.” But it has stressed it’s the responsibility of law enforcement to build a case before her office can consider charges.“The Cook County State’s Attorney's Office is committed to seeking justice on behalf of anyone harmed during Operation Midway Blitz when the evidence and the law support a prosecution,” Burke’s office said in a statement Tuesday. Cook County State’s Attorney Eileen O’Neill Burke speaks to reporters in August 2025.Pat Nabong/Sun-Times Martinez’s shooting is now being reviewed by a unit tasked with “investigating all officer-involved shootings occurring within the city limits,” including any shootings involving outside law enforcement officials, according to CPD’s annual report.Many of the detectives there once worked as lead homicide investigators, the report says. As of July, there were 31 department members assigned to the unit, according to Chicago’s inspector general’s office.The unit was created in 2017, in the wake of the fatal police shooting of teenager Laquan McDonald.Despite early hints of a federal investigation into Martinez’s shooting — including by the U.S. attorney’s office in South Bend, Indiana — Martinez told reporters this month she’d yet to be interviewed by the feds.“If the federal government refuses to act, state and local authorities must do so,” Martinez said Aug. 10.Neither the FBI nor the northern Indiana U.S. attorney’s office would comment Tuesday. Homeland Security released a statement that referred to Martinez as a “rioter” and accused her of ambushing federal agents — without acknowledging that the Justice Department in November dropped the criminal charges it had initially filed against her.Homeland Security has said Exum “was placed on administrative leave” but has offered no additional detail. Related DHS says Border Patrol agent was ‘placed on administrative leave’ after shooting Chicago woman 5 times Martinez is expected to file a lawsuit against the federal government in the coming weeks. She was shot five times in the October incident, and left with seven wounds.“We patiently waited for nearly a year for the FBI or the [Justice Department’s] Civil Rights Division to do their job and investigate the attempted murder of Ms. Martinez by Border Patrol Agent Charles Exum,” Parente said Tuesday.“After learning they are unwilling to do their job, or even investigate the facts, we now turn to the Cook County State’s Attorney’s Office for help ensuring that the concepts of justice and accountability still exist in the United States of America.”Cook County Commissioner Jessica Vasquez, who organized the Aug. 10 “mass filing” event, welcomed the police department’s investigation of Martinez’s shooting.“Marimar deserves a thorough investigation and so does every person who filed a police report on and before Aug. 10,” Vasquez said. “We urge CPD to investigate each allegation fully and refer cases to the Cook County State’s Attorney’s Office when the evidence supports prosecution.” Cook County Commissioner Jessica Vasquez speaks at the opening of the Gran Festival Colombiano at Humboldt Park in July 2025.Candace Dane Chambers/Sun-Times The CPD unit handling Martinez’s case is approaching it like any other police shooting, the source told the Sun-Times. Still, the unit will have to follow a protocol Burke established earlier this year for seeking charges against federal immigration officials.That protocol says a grand jury “may issue a subpoena to a federal law enforcement agent who is a material witness that could provide relevant evidence to the grand jury.” It says a prosecutor should seek that person’s appearance with a subpoena and what’s known as a Touhy request.The same approach may be taken to seek physical, documentary, video or other evidence, it says.However, Burke’s protocol acknowledges that “the federal government, including its law enforcement entities, are not required to comply with any subpoena issued by a state prosecutorial body, and [the Cook County state’s attorney’s office] does not have jurisdiction or authority to mandate subpoena compliance.”State prosecutors looking to charge federal agents must also consider whether the federal agents were acting reasonably while fulfilling their duties. Related Cook County’s top prosecutor outlines plan to charge ICE agents with crimes Martinez has said she was on her way to donate clothes at a church Oct. 4 when she crossed paths with Exum’s Chevrolet Tahoe. She began to follow it in her Nissan Rogue and continued for at least 20 minutes, honking her horn and yelling “la migra” to warn others that immigration officers were present.Martinez told police this month that, when she pulled her Rogue beside the Tahoe, the Tahoe driver “started swerving into her vehicle striking her car on the right front side,” according to her police report.She told police she “came to a complete stop” but then “proceeded to go around the Chevy Tahoe to avoid confrontation and to get to safety,” according to the report. That’s when she said she saw someone “open his vehicle door with his gun drawn, step out and [fire] shots towards her vehicle as she was driving past him.”Body-camera footage of the incident released in February showed Exum appearing to turn his steering wheel to the left, toward Martinez’s car. He did so right after agents inside the Tahoe he was driving said, “it’s time to get aggressive” and “we’re going to make contact, we’re boxed in.” Parente has disputed Exum’s claim to the FBI that Exum fired all five shots at Martinez through her front windshield. Parente said three were fired into the passenger side of her Rogue, a fourth kicked “out the rear passenger window,” and a fifth went from the back of her car through the front passenger seat.Martinez pulled over at a repair shop after the shooting, was taken to a hospital and eventually into federal custody. Authorities alleged Martinez and another man “rammed” Exum’s car. The charges against the pair were dropped Nov. 20 by U.S. Attorney Andrew Boutros’ office.Martinez then began to speak out, especially after immigration authorities in Minneapolis killed Renee Good and Alex Pretti. She attended President Donald Trump’s State of the Union address as a guest of Democratic U.S. Rep. Jesus “Chuy” Garcia.She later testified before the House Homeland Security Committee in Washington, telling lawmakers that if immigration agents aren’t held accountable, “more people are going to get hurt.” ...read more read less