A shocked courtroom heard Derek Rosa tell police he stabbed his mother to death in her sleep as his baby sister slept next to her in the bed.

After hearing the teen's taped confession, Miami Dade Circuit Judge Richard Hersch rejected a defense motion to move Rosa out of the adult jail and into a juvenile facility. The defense says it is unconstitutional to keep Rosa in an adult cell, claiming he is being kept in unsustainable conditions and is only allowed outside the cell for 20 hours a week.

After rejecting the motion, the judge orders Rosa to be held in the Miami-Dade Metro West Detention Center until his unscheduled trial begins.

Reportedly, the night Derek Rosa stabs his mother to death, he makes six Google searches including,

“What is the best place to stab someone?” "
"Is a small knife good for killing?” “
"Is it easier to kill someone with a small knife?”
“Can a knife cut through bone?”

He also searched for an image of The Carotid Artery diagram. The DailyMail reports the last search made that night was to inquire about a machine gun.

Derek Rosa claims in a police interview that his stepfather owns two guns and he planned to shoot himself after the stabbing but didn't go through with it.

Joining Nancy Grace Today:

Matthew Mangino – Attorney, Former District Attorney (Lawrence County); Author: “The Executioner’s Toll: The Crimes, Arrests, Trials, Appeals, Last Meals, Final Words and Executions of 46 Persons in the United States;” Twitter: @MatthewTMangino
Caryn L. Stark – NYC Psychologist, Trauma and Crime Expert; Twitter: @carynpsych, Facebook: “Caryn Stark”
Pat Diaz – Former Miami Dade Police Homicide Detective, Private Investigator in South Florida
Dr. Kendall Crowns – Chief Medical Examiner Tarrant County (Ft Worth) and Lecturer: University of Texas Austin and Texas Christian University Medical School
Alexis Tereszcuk – CrimeOnline Investigative Reporter, Writer/Fact Checker at Lead Stories; Twitter: @swimmie2009

See omnystudio.com/listener for privacy information.

Honor Student, 13, Stabs Mom DEAD IN NECK, Next to Infant Daughter: CONFESSES