CHICAGO (CBS) — Avontea Boose has a question for the Midlothian police officer who shot and killed the father of her children.

“Why did you pull the trigger?”

Boose said she wants Midlothian police to publicly identify the officer who shot and killed the father of her children. She said she doesn’t understand why he was mistaken for a suspect.

“I want to know why he did it. Everyone was screaming ‘he’s a security guard’ and they were still shooting at him,” Boose said.

Roberson was working security at Manny’s Blue Room Lounge in Robbins early Sunday morning when shots rang out inside the bar. Illinois State Police said he was trying to subdue the shooting suspect when a Midlothian police officer shot and killed him.

Boose said Roberson always wore clothing that identified him as a security guard when he left for work. Illinois State Police said he was in plain black clothing with no security guard markings, although there are some witnesses accounts that challenge that.

Boose and Roberson had a nine-month-old son together. And just 10 days before the shooting she found out she was pregnant with Roberson’s second child. She said this has devastated her family and she is now calling on Midlothian police to release the officer’s identity.

RELATED: Midlothian Police Chief Calls Shooting A “‘Blue On Blue’ Friendly Accident”

Midlothian police told Boose’s attorney that is up to the Illinois State Police.  But state police said it’s not up to them to name an officer that is not part of their department.