Man accused of stabbing 2-year-old son for 'keeping him awake': Police

— -- Charges are expected for a Chicago father who police said confessed to the murder of his 2-year-old son, who was found dead in a garbage bag.

Rolando Ortiz, 37, was arrested late Wednesday after he allegedly fled the scene in Chicago's Little Village neighborhood, where his 2-year-old son, Mateo Aguayo, was found unresponsive by Chicago Police officers earlier that day in an upper floor of an apartment building, Chicago Police Detective Cmdr. Brendan Deenihan said in a press conference today.

Ortiz allegedly confessed to the crime after he was arrested, Deenihan said. He allegedly killed his son because he was "very frustrated that he could not sleep," and Aguayo was "running around and keeping him awake," Deenihan said.

Ortiz allegedly told investigators he grabbed his son, held him down and stabbed him, Deenihan said.

After realizing what he had done, Ortiz allegedly told investigators he tried to cut his own wrist before emptying a garbage bag full of clothes and placing the toddler in the bag, Deenihan said. Ortiz allegedly then tried to call his wife before finally reaching his wife's sister and telling her what he had done, Deenihan said.

When Ortiz's sister-in-law asked others in the building to check on them, they allegedly found Mateo in a garbage bag and Ortiz bleeding from his wrist, Deenihan said.

Ortiz allegedly fled as officers were dispatched to the scene but was later apprehended in Kankakee County during a traffic stop and was "immediately" brought back to the Chicago area, Deenihan said.

"This is the kind of slaying that keeps police officers up at night," Chicago Police Superintendent Eddie Johnson said, describing Mateo as an "innocent kid whose trust and safety was betrayed by the one man he should never have to question."

Ortiz allegedly told investigators he intended to go to Mexico, Deenihan said.

Authorities are in possession of the murder weapon, Deenihan said, adding that drugs and alcohol do not appear to have played a role in the murder.

The couple has six other children, but there are no prior incidents on record involving children who were harmed, Deenihan said.

Formal charges have not yet been filed against Ortiz but are expected from prosecutors, Deenihan said.

"I’d like to say to Mateo’s family, that, as a father, I know there’s nothing we can ever do to bring Mateo back to you, but I hope that this will give you some level of closure as you keep Mateo’s memory close to your hearts," Johnson said.

ABC News' Jessica Zellermayer contributed to this report.