A judge ordered William Zientek held in jail, while he awaits trial for the murder of Dr. Olga Duchon.
And the victim's sister is now trying to gain custody of the couple's child.
Duchon's family and friends vow to be at every hearing for the man accused of killing her.
"We're committed to make sure this murderer in prison for the rest of his life," sister Tatiana Maya said.
Zientek is charged with murder in the death of his former girlfriend and the mother of their 4-year-old daughter.
Prosecutors say Zientek hit Duchon twice with a baseball bat before shooting her.
"Dr. Olga Duchon was one of the finest humans to ever walk the earth. She gave endlessly to her patients, to her family. That's why we're all so devastated," Paul Wharton said.
Zientek's attorney claims Duchon brought a gun to his Barrington townhouse, where they were to meet to discuss child custody.
And during a struggle over the gun, it discharged, killing her, the attorney said. It happened in the presence of their daughter.
"This is a tragedy because the mother of his child is now deceased, and this is not something he wanted or expected as an outcome," attorney Tom Glasgow said.
Her family says Duchon hated guns, and filed an order of protection against Zientek in 2021, requiring him to surrender his firearms. Relatives now say they're trying to protect her child.
"Her daughter was everything to her, her daughter and her work, everything," Maya said.
The case is due back in court early next month.
Duchon's sister said she plans to be in a different court later next month, asking for permanent custody of the couple's child.