Two days after a 19-year-old woman was fatally shot through the window of a second-floor apartment in Washington Park, a witness told a Chicago police detective, “This is gonna be taken care of anyways.”
And in fact the April 2, 2019, murder of Jiaerra Harris was the first of at least five intertwined shootings that involved a neighborhood gang conflict, a deadly attempted carjacking downtown, a mass shooting at a subsequent memorial and the murders of two witnesses.
Records obtained by the Tribune detail how one of the Chicago Police Department’s most effective homicide investigators recently closed that 5-year-old cold case, helping to raise the department’s murder clearance rate to its highest level in more than a decade.
CPD’s homicide clearance rate reached 71% last year — up from 55% in 2024 — amid a sharp decline in murders that helped buoy the figure. Records obtained by the Tribune show CPD detectives cleared fewer cases in 2025 — 296 — than in any year since 2019.
That means detectives effectively cleared cases among a smaller number of homicides, and continued to count the clearance of older cases in the department’s newest figure. In fact, of the cases cleared last year, records show more than 60% of them originated in years prior to 2025, the oldest being from 1987.
The clearance rate is calculated by dividing the number of homicide cases opened in a year by the number of homicide cases closed in a year. It’s a formula used by police departments across the country and remains the closest thing available to an objective measure of CPD’s effectiveness in investigating the most serious crime in Chicago.
‘I hit my targets’
On April 2, 2019, Jiaerra Harris attended a small birthday party for a friend at an apartment in the 6100 block of South Martin Luther King Drive. Not long before midnight, she sat in the kitchen while others shot dice in a nearby bedroom.
The guest of honor, turning 23, was recently paroled. Two years earlier, while being arrested for illegal gun possession a few blocks away, he told officers, “It is what it is. I keep my (expletive) on me.”
“I hit my targets,” he added.
A few days before the party, witnesses told police, a relative of Harris was in a fight with Lonell Irvin, who police said is a member of a nearby faction of the Black Disciples.
As Harris was in the kitchen, a bullet ripped through the open window, fatally striking her. One of the other attendees, a roommate, saw Irvin running away while holding a gun. Another person called 911 and police and paramedics soon arrived. Harris was pronounced dead about 30 minutes later.
Police records indicate Harris was shot three times, though investigators found only one spent bullet casing in the building’s side walkway. Another casing was found in the kitchen where Harris was shot.
Her family declined to be interviewed for this story.
The man who was celebrating his birthday was taken into CPD custody two weeks later on an unrelated charge. While at the police station, the detective asked again about the killing.
He refused to look at a photo array of potential suspects, but said he “heard on the street” that the shooting was retribution for the earlier fight. The witness told police he believed Irvin to be the shooter.
Violence ripples out
Irvin, 22, was dead just 10 days later.
On April 26, 2019, Irvin was driving a stolen Volkswagen SUV in the first block of West Ida B. Wells Drive when he rear-ended a BMW sedan that was waiting at a red light. The BMW driver got out, but Irvin, armed with a handgun, soon forced him into the car’s front passenger seat as Irvin got behind the wheel.
In the car, when Irvin briefly turned his attention away from the victim, the man reached for his own gun and shot Irvin three times in the head. He was pronounced dead at the scene. CPD logged the shooting as a justifiable homicide and the BMW driver, a legal gun owner, was not cited.
Even with Irvin’s death, the investigation into Harris’ killing continued.
On Dec. 7, 2019, the other witness who identified Irvin as the shooter — the man who was celebrating his birthday — was found shot to death in the backyard of a home in south suburban Harvey. Police officials there did not respond to a request for comment from the Tribune.
Two weeks later, on what would have been Irvin’s 23rd birthday, a house party was held in his memory in Englewood. Police officials estimated that about 70 people were in the home in the 5700 block of South May when two gunmen opened fire. Thirteen people were shot and wounded, four of them critically.
“It’s a terrible tragedy and, frankly, an act of cowardice,” former Mayor Lori Lightfoot said shortly after that shooting. “We can’t normalize this kind of behavior and tragedy in this city.”
Two men were later charged and convicted in connection with the shooting, records show.
The case changes hands
Meanwhile, the detective who initially investigated Harris’ killing retired from CPD. The case was reassigned to another detective who, as an officer, responded to the scene on the night of the shooting, records show.
In February 2021, the detective made contact with the other man who lived in the apartment when Harris was killed. The man “admitted to being an eyewitness and subsequently identified (Lonell Irvin) as the offender,” though he refused to sign or initial the photo.
A month later, that witness was killed, too, apparently in retaliation for a house fire he caused when he tried to heat a home in the 7900 block of South Anthony Avenue with a space heater.
Records indicate he returned to the block in March 2021 and was recognized by a neighbor as the person who started the fire. The neighbor then shot the witness and fled. CPD records indicate that killing was cleared in 2024 after prosecutors declined to seek an arrest warrant.
CPD Detective Patrick Deenihan, a cold case investigator in Area 1, took over the Harris investigation in early 2024 after the second detective on the case was promoted to sergeant, records show. While reviewing the investigation, his fellow officer told Deenihan that “this case was one that could potentially be cleared.”
CPD declined to make Deenihan available for an interview.
Records show Deenihan sought out two other witnesses who were in the apartment playing dice on the night of the shooting, including the man who initially told police, “This is gonna get taken care of anyways.” They also heard, secondhand, that Irvin was the shooter, though neither saw him at the scene.
The detectives stayed in contact with Harris’ parents throughout the investigation, and in March 2025, Deenihan told them the case would soon be closed.
With the two secondhand identifications, paired with the statements from the two dead witnesses, Deenihan submitted the case to his supervisors to be closed in August 2025 via “command channel review.”
That process requires an evaluation of the investigation by a detective’s sergeant, lieutenant and, ultimately, commander, according to a CPD spokesperson. It is one of the ways a homicide can be pronounced “cleared.”
“In each investigation, homicide team supervisors and detective area leadership provide guidance and oversight to ensure all steps are taken to bring offenders to justice,” CPD said in a statement to the Tribune.
“Cases are cleared closed through exceptional means only after all the necessary investigative steps are taken and the case will not proceed to court,” the statement read. “Command channel review is conducted to ensure an exceptionally cleared closed designation is appropriate and consistent with a complete and thorough investigation.”
Prior to any charging decision, investigating detectives and supervisors regularly meet with prosecutors in the Cook County state’s attorney’s office.
“These meetings offer detectives an opportunity to present updates on witness statements, forensic results, and physical and digital evidence to Assistant State’s Attorneys, helping determine whether sufficient evidence exists to charge a suspect and proceed to trial,” CPD’s statement added. “If the investigation is to continue, supervisors and detectives receive clear direction on the necessary next steps to advance the case for prosecution.”
An officer climbs the ranks
Deenihan was hired by CPD in 1997 and was initially a patrol officer in the Harrison District (11th) on the city’s West Side, city personnel records show. He was promoted to detective in 2000 and is the older brother of Brendan Deenihan, CPD’s former chief of detectives.
Before Area 1, he was assigned to Area 4, which covers the Ogden, Harrison and Austin districts, three of CPD’s most violent.
In the last quarter century, he has been one of the most effective of all CPD homicide investigators. Records reviewed by the Tribune show that Deenihan has cleared 51 cases since 2012 — roughly the time he was assigned to Area 1 — more than any other CPD detective but one.
As is often the case, though, most of the clearances have come without an arrest.
The handful of cases cleared via charging since 2012 have all led to convictions, according to Cook County court records. However, a man who was charged and convicted in a 2011 West Side murder, investigated by Deenihan and his partner, recently had his 51-year prison sentence vacated. A hearing is scheduled for next month to argue if the man should receive a certificate of innocence, records show.
Besides the Jiaerra Harris killing, Deenihan cleared three more cold cases in 2025: a 2001 murder in McKinley Park, a 2009 killing in Englewood and another from 2013 in Back of the Yards. Records show the state’s attorney’s office declined to bring charges in each of those three.
Records show Deenihan was assigned to investigate the 2017 murders of drill rappers FBG Brick — the brother of FBG Duck — and Coby Mack in the 6300 block of South St. Lawrence. That case was cleared in 2024 after CPD determined that the shooter died while he was held at Cook County Jail in connection with a separate murder case, records show.
