Discretion is advised.

This is 10-minute murder.

47-year-old Yumi Hoy was becoming more and more frightened of her teenage daughter,

18-year-old Isabella Guzman.

The two of them had never had a great relationship, and they frequently argued ever since

Isabella was a little girl.

The arguing got so bad that when Isabella was only nine,

she spent a portion of time living with her biological father

in the hopes that some distance would improve the relationship with her mother.

According to Isabella's stepdad, Ryan Hoy,

Isabella continued to disrespect her mother throughout her teenage years.

After she dropped out of high school, the relationship deteriorated even further.

Her behavior escalated to include screaming at Yumi and even spitting at her.

The assaults and threats came to a head on Wednesday the 28th of August 2013,

when Yumi received a threatening email from her daughter. The email was simple, saying,

You will pay. But Yumi was so shaken by it that she and Ryan decided to call the police

and report that their daughter

had threatened to harm them.

As well as calling the police about the threat, Yumi and Ryan called Isabella's biological

father and asked him to come and talk to his daughter.

Robert Guzman had always had a much better relationship with Isabella, and Umi hoped that he might be

able to calm her down. Robert was aware that Umi and Isabella always had a strained relationship.

...