"I believe this was a series of heinous and depraved acts," the police chief said

An Indiana father has been charged for fatally shooting his 9-year-old daughter in the head while teaching his two sons about the dangers of playing with guns.

According to court documents, Eric Hummel, 33, from Hobart, Indiana, was talking to his sons on June 10, when his daughter Olivia walked into the room. Believing the gun was not loaded, he pointed it towards her and shot, he told police.

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He was charged earlier this month with neglect of a dependent resulting in death, battery resulting in death to a person less than 14 years old, reckless homicide and two counts of neglect of a dependent, court records show.

On Wednesday, according to The Chicago Tribune, he was read his charges and potential penalties. He faces 20 to 40 years on the neglect of a dependent resulting in death charge, a Level 1 felony. Hummel entered a not guilty plea.

‘I Thought it Was Empty’

When an officer from the Hobart, Indiana, police department arrived at the scene, he allegedly saw Olivia lying in the doorway of the bedroom with Hummel kneeling next to her. Hummel told the officer he had been doing chest compressions, according to a police report obtained by PEOPLE.

“She’s dead, she’s dead. I thought it was empty, you can kill,” Hummel told the officer, according to the report.

Hummel, who’d placed the gun atop a piece of furniture, allegedly told the officer, “I was showing the boys the gun and told them not to ever play with it because it can kill someone, then she walked in in the room and I pointed it at her and pulled the trigger, thinking it was empty,” the police report states.

A little later, a detective arrived at Hummel’s home and found him in the back of the home. After introducing himself and asking if he was okay, Hummel responded that he was just numb. His eye’s had a ring around them, as if he had cried earlier, and his hands were trembling, according to the police report.

The report states that Hummel’s 10-year-old son told the detective that Hummel had entered the room with the gun and said something to the effect of, “You should never mess with the gun.” At the time, there were no bullets in the gun, the boy contended.

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Hummel 9-year-old son told the detective he knew the gun wasn’t loaded at first because “when he shoot it at me it just made a little pop sound,” the report states. The boy said Hummel had allegedly pointed the gun at him “probably like two times” and “a few times” at this brother.

Hummel then loaded the gun and stated “never use a gun, don’t play with guns,” the 9-year-old said, according to the report. Olivia then walked in the room and Hummel — who, according to the 9-year-old, forgot the gun was loaded — turned around and allegedly said, “See don’t play with guns” and “he shooted her,” the report alleges.

After Hummel was brought to the police station, he called Olivia’s mother, Mandy Zormier, and told her to get to the hospital because Olivia was dead. The initial responding officer allegedly overheard him tell her, “I shot her, I’m so sorry.”

He also heard him say, “It was stupid, so stupid.” He then began to cry, the report states.

‘Series of Heinous and Depraved Acts’

According to The Chicago Tribune — which obtained the 5-minute 911 call placed by Hummel — Hummel told the dispatcher, “This can’t be real.”

During the emotional call, Hummel asks the dispatcher if he should press on Olivia’s chest, saying she has blood everywhere and isn’t breathing.

“Please don’t go. Oh my God. Please don’t go,” he said, whispering, the paper reports.

At a press conference, Hobart Police Chief Richard W. Zormier said, “I believe this was a series of heinous and depraved acts committed by the suspect on June 10. His actions that day endangered the lives of all three children and ultimately stole the life of Olivia, an innocent 9-year-old girl.”

Zormier added, “His actions caused the death of Olivia and likely scarred the boys emotionally for life.”