AURORA | An Aurora teen who police say stabbed her mom 79 times last summer has pleaded not guilty by reason of insanity to first-degree murder charges.
Isabella Guzman, 18, entered the plea during a hearing in early December, according to Arapahoe County court records. She was later sent to the Colorado Mental Health Institute in Pueblo for a psychiatric evaluation.
Guzman is accused of killing her mother, Yun-Mi Hoy, 47, on Aug. 29 in the bathroom of the family’s home near East Yale Avenue and Parker Road. She has been jailed since police arrested her a day after the gruesome slaying.
It appears from court records that officials expect Guzman’s psychiatric evaluation to be lengthy. A judge scheduled the next hearing in the case for Feb, 28, but said Guzman does not have to appear, she does have to appear for another hearing March 21.
The case has moved slowly through the courts since Guzman’s arrest. Last fall she waived her right to a hearing on whether there was enough evidence for prosecutors to take the case to trial on first-degree murder charges. Later, she was sent to Pueblo for evaluations.
According to an arrest affidavit filed against Guzman, she had been feuding with her mother in the days leading up to the attack.
Hoy’s husband and Guzman’s stepfather told police that two days before the attack, Guzman threatened her mom and spit in her face.
A day later, Guzman sent her mother an email that said “you will pay,” the stepfather told police.
The day of the attack, Hoy called police because she was scared her daughter would harm her, but after police spoke with the family they determined the family squabble had been solved.
On the night of the attack, the stepfather told police his wife went upstairs to take a shower and he heard a thumping sound before she called his name.
When he went upstairs, he said he saw Guzman in the bathroom pushing the door closed and believed she was assaulting his wife. A few seconds later Guzman walked out of the bathroom with a knife her in her hand.
An autopsy later said Hoy was stabbed 31 times in the face and 48 times in the neck.
Guzman fled the home after the slaying, police said, but officers later found her hiding at a parking garage a short distance away. She was arrested on a first-degree murder charge and has been held without bond since.
During a court appearance last fall Guzman was seen making faces at television cameras.


Another human monster.
I don’t think insanity will fly when her comment to her own mom, telling her she would pay, (shows premeditation). This is a very vile kid and will never ever change. I say throw away the key. Insanity is not an excuse for murder and I am sick of angry people who think they can kill people yelling insanity. You can’t murder. Thats the law but this girl premeditated and should not ever get out of prison. ever. Let her rot in there and with so much hate that she has throw her in with other prisoners and see how long she last. Her life as she knew it should be gone for dishonoring her mother. When she spit in her moms face she should of had her teeth knocked out and kicked out of the home. No insanity. SHE PREMEDITATED. SHE DID THIS OUT OF ANGER AND CUZ SHE DID NOT GET WHAT SHE WANTED. SHE HAS HAD NO REMORSE AND EVEN WAS DISRESPECTFUL IN THE COURT. COME ON JUDGES GET IT TOGETHER.
She could have had a number of psychological conditions some can begin as early as 6 years old, and she couldn’t have been mentally stable during the murder because of the number of stabs. Theirs no excuse for murder but their has to be a reason for what drove her to it. I’ve been looking into the case and I saw a news interview with one of her neighbors and they said they had been living by them for years and didn’t even know that they had a daughter until recently. Either way justice will be served but I just wonder what kind of life Isabella had, I hope those details are investigated as well.