UPDATE: Court documents reveal chilling details of fatal stabbing

Tucson teen accused of killing mother with dumbbell, large butcher’s knife
The Tucson Police Department said Mary Ainuu, 60, died after she was stabbed in her home in the...
The Tucson Police Department said Mary Ainuu, 60, died after she was stabbed in her home in the Rita Ranch area late Tuesday, Jan 11. Ainuu's 13-year-old son has been arrested on a charge of first-degree murder.(Live 5/File)
Published: Jan. 12, 2022 at 2:35 PM MST|Updated: Jan. 14, 2022 at 1:25 PM MST
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TUCSON, Ariz. (KOLD News 13) - Court documents have revealed chilling details about the night a Tucson teen allegedly killed his own mother with a large knife and a dumbbell.

According to the Tucson Police Department, 60-year-old Mary Ainuu was attacked in her home near South Houghton and East Rita roads late Tuesday, Jan. 11.

The TPD said Ainuu’s 13-year-old son was arrested and charged with first-degree murder. KOLD has decided not to identify the teen due to his age.

According to court documents, Ainuu suffered multiple stab wounds and died at a local hospital.

The suspect allegedly had been getting into trouble because he was playing video games when he wasn’t supposed to.

On the day of the stabbing, the teen allegedly went into the family’s kitchen and grabbed a large butcher’s knife and a sharpener.

The suspect allegedly used the sharpener and went to the living room, where his mom was sitting down.

According to the court document, the suspect and Ainuu had a brief conversation before he hit her in the head with a five-pound dumbbell.

The suspect then allegedly stabbed Ainuu eight or nine times before she was able to get away.

Ainuu ran to a neighbor’s home and asked for help.

According to the court document, the suspect told police he then ran into his room, grabbed his backpack and ran away. He told investigators his mother was not armed and that he was wearing gloves when he stabbed her. He said he threw the knife in someone’s backyard as he ran away.

Police said they found the gloves on the suspect and the dumbbell inside the home. The documents did not mention if the knife was ever found.

The suspect had a cut on his forearm and told police it happened during the stabbing, according to the court document.

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