He then allegedly turned the gun on himself.
The shooting happened Thursday just before 7:20 a.m. in the 1400-block of West Thome Avenue near Northside Catholic Academy in Edgewater, CPD said.
Two men were outside when they were shot, Chicago police said.
Nick Calzaretta, 37, was shot and later died at the hospital.
Ammar Houssamo, 53, was charged with first-degree murder and two other gun-related charges in the shooting, police said.
Police said Houssamo was taken to St. Francis Hospital in critical condition.
Court documents revealed that Calzaretta was married to the Houssamo's ex-husband.
In September 2023, Calzaretta filed an order of protection against Houssamo. The order was terminated in April 2024.
The order mentioned references to suicide.
Calzaretta's brother said the two had a history of problems.
"'How do we tell mom?' I said, 'she's going to be so brokenhearted.' And I said to him, I said, 'she's going to die of a broken heart when you tell her,'" said Russell Calzaretta, as he recounted phone calls with family after his older brother was killed. "Nick had shared with me that he was harassing him and Cam, and would send endless text messages, very harassing messages to Nick."
Russell Calzaretta said he wonders if the protective order alone would have been enough to stop the shooting.
"What was Nick supposed to do, you know? Ammar's coming at him with a gun. Is Nick supposed to hold up the protective order and that is his shield?" Russell Calzaretta said.
Attorney Benna Crawford with Legal Aid Chicago admits the judicial process surrounding protective orders can be grueling.
"I think it can be a really demoralizing process to have to fight so hard to keep yourself safe when you're presented with such a serious safety threat, and to feel like you're the one who is having to push so hard for that," Crawford said.
She says this case is a good reminder that pursuing protective orders to the fullest extent helps judges revoke Firearm Owner Identification cards and law enforcement to confiscate guns when the victim's safety is at risk.
"Getting firearms out of the hands of people who engage in this type of behavior can be the difference between whether somebody lives or dies," Crawford said.
Russell Calzaretta said it's hard to think of his older brother becoming a statistic and hopes Illinois lawmakers will take notice of this case. In the meantime, he'll hold on to the memories.
"He had this belly laugh that no matter where you were in the house, wherever you were, you could hear his laugh," Russell Calzaretta said.
Houssamo was due in court on Tuesday. He was denied a pretrial release.
If you are experiencing suicidal, substance use or other mental health crises please call or text the new three digit code at 988. You will reach a trained crisis counselor for free, 24 hours a day, seven days a week. You can also go to 988lifeline.org or dial the current toll free number 800-273-8255 [TALK].
You can contact the Illinois domestic violence hotline at 1-877-863-6338 click here for more information.