MESA, Ariz. -- The 16-year-old accused of killing his mother with the help of a 17-year-old friend should find out soon if he and his alleged accomplice will be charged and tried as adults.
The boys were arrested Saturday after the body of Tina Helms Spencer was found inside a backyard shed at her Mesa home.
The teens were booked into the juvenile detention center. If the decision is made to try them as adults, they will be moved to the Fourth Avenue Jail.
According to police, the 16-year-old told them that he killed his mom because he was upset that he was grounded.
Investigators said the teen also went after his stepfather. It was the stepfather who called 911 at about 4 a.m. Saturday. He told the dispatcher the teen had attacked him. He did not know at the time that his wife was dead already.
"This kid just kept assaulting and a several-minute struggle ensued," Mesa police Sgt. Tony Landato said.
According to Landato, the stepfather escaped and went to a nearby home to call the police.
By the time police arrived at the home in the neighborhood northeast of Gilbert and Baseline roads, the teen was gone, as was his mother's car. Seeing obvious signs of struggle, officers searched the property. They discovered Spencer's body in the shed.
The investigation took detectives to the home of the teen's friend.
"While we were there interviewing him [the friend], our 16-year-old suspect arrived at the residence and was quickly taken into custody by our detectives," Landato said.
Talking to the 16-year-old, police learned that he allegedly plotted to kill his mom and stepfather because he was mad that they had grounded him. He told detectives that he recruited his friend to help.
According to Landato, the 16-year-old attacked Spencer as soon as she came home. Detectives believe he killed her and then moved her body to the shed. They also believe the teen and his 17-year-old friend tried to clean up the scene and dispose of evidence.
The 17-year-old had already left when the stepfather arrived home and was attacked.
The 16-year-old is facing charges of murder and attempted murder, among others. His 17-year-old friend is facing charges of first-degree murder as an accomplice and tampering with evidence.
Police have not released the name of either boy. What happens next depends on the court's decision about whether they should be tried as adults. That ruling could come as soon as Monday.