Prosecutors say a man attacked his ex-girlfriend, who was a mother and a doctor, with a bat and then fatally shot her in Barrington while their young child was present.
William R. Zientek, 46, of Barrington, was charged with one count of first-degree murder, a Class M felony.
The Barrington Police Department and Barrington Fire Department responded around 5:40 p.m. Sunday to The Arbors at Barrington Apartments in the 400 block of West Russell Street for a report of a shooting.
Police officers arrived to find a woman suffering from a gunshot wound.
Lake County Coroner Jennifer Banek identified the woman as Olga Duchon, 42, of Vernon Hills.
The Barrington Fire Department provided emergency treatment to Duchon.
Paramedics transported Duchon to Advocate Good Shepherd Hospital in Barrington where she was pronounced dead, police officials said.
Banek said an autopsy performed Monday on Duchon showed she died from a gunshot wound to the chest.
Police officials said the incident was a domestic-related incident between family members.
Prosecutors revealed Wednesday that Zientek and Duchon had previously been in a dating relationship and had a 3-year-old child in common.
Zientek called Duchon on Sunday to have a face-to-face conversation.
Duchon drove to Zientek’s residence in the 400 block of West Russell Street and was attacked shortly after arriving.
Prosecutors said Zientek struck Duchon in the back of the head with a baseball bat.
He then struck the woman in the right temple with the bat, causing her head to split open and fracturing her skull, prosecutors said.
Prosecutors said Zientek shot Duchon once with a gun that had previously been reported stolen.
The stolen gun report was made around the time that Duchon obtained an order of protection against Zientek in 2021. The order of protection resulted in Zientek’s FOID card being revoked.
The couple’s relationship had come to an end due to a disagreement about Zientek keeping firearms in the home, prosecutors said.
The 3-year-old child was present in the home at the time of the murder.
Officers took Zientek into custody at the scene after they received a 911 call from the man.
Officials said Tuesday afternoon that both the Barrington Police Department and the Major Case Assistance Team (MCAT) completed a “thorough investigation” of the incident.
The Cook County State’s Attorney’s Office subsequently approved the first-degree murder charge against Zientek.
Zientek was transported to the Cook County 3rd District Courthouse in Rolling Meadows on Wednesday morning for a detention hearing.
Cook County Judge Ellen B. Mandeltort granted a petition filed by the state’s attorney’s office to detain Zientek in custody pending trial.
Mandeltort said no conditions of release could protect the community from Zientek and that he poses a real and present threat.
Duchon was a doctor in endocrinology affiliated with Northwestern Medicine as a member of the organization’s medical staff treating patients independently.
She was also an assistant professor at Rosalind Franklin University of Medicine and Science.
“We are learning about this tragic event in real time and we are devasted to hear this news. Our sympathies go out to her family during this difficult time,” a spokesperson for Northwestern Medicine said.
Maria Hrycelak, the President of the Ukrainian Medical Association of North America Foundation, told news outlets that Duchon had been the featured speaker during a lecture on obesity management through the use of weight loss medication.
The lecture was held in Wheeling on Sunday afternoon, just hours before her death.
Hrycelak described Duchon as “well-trained” and “smart.”
Zientek, who is being held in the Cook County Jail, is scheduled to appear in court again on December 13 for a status hearing.