"We need to get moving on this," Frost told attorneys, while the boy sat handcuffed between his father and defense attorney Todd Sessions.
Sessions told the judge that the mental health analysts who evaluated the teen need up to 60 days to file their reports. He asked to put off setting a date for the certification hearing so they have time to look over the reports.
Frost opted to set the certification hearing dates anyway, but also scheduled an April 17 court date to address the status of those medical reports.
Prosecutors have said they will push for the teen to be charged as an adult. But Sessions said outside of court that he thinks the 15-year-old should be kept in the juvenile system.
"Because of his age," Sessions said. "Because of the resources available [within the juvenile system.] It's in his best interest."
At the teen's last court appearance in November, Frost ruled that police violated the 15-year-old boy's Miranda rights when investigators continued to ask him questions about the double-slaying at his home on May 22, 2013, after the teen twice refused to waive those rights.
At that time, Frost ruled that the statements that the teen made at the Davis County Sheriff's Office interrogation room would be suppressed and not used against him in the case.
The decision came after a stipulation was submitted by both the teen's attorney and Davis County prosecutors.
Defense attorney Todd Utzinger said in November that on the morning of May 23, four detectives from the sheriff's office put the teen into an interrogation room and continued to pressure him to give statements even after he refused several times and had fallen asleep twice.
Prosecutors have declined to answer questions about how the loss of the boy's statements to police might affect the case.
But certain other spontaneous statements made by the teen can still be used by prosecutors, according to attorneys and court documents. Police have previously said that traces of blood found on the teen link him to the crime scene.
Davis County Sheriff Todd Richardson previously has said that the bodies of the two victims were found in their West Point home on May 22 around 7:35 p.m. He said the slain boys ages 4 and 10 appeared to have suffered "penetrating knife wounds."
Deputies rushed to the home at 120 S. 1660 West after the boys' mother called 911 to report finding her 4-year-old son dead on the floor of the home, and her 15-year-old and 10-year-old sons missing.
Deputies found the 10-year-old's body in another part of the house, then issued a missing person alert for the 15-year-old, who was found late that night in nearby Layton.
The teen was found walking on the street by Layton police about 11:30 p.m., about eight miles from the crime scene.
He was taken to the hospital to be checked before questioning and then booked into the Farmington Bay Youth Detention Center on suspicion of two counts of homicide, Richardson said.
The teen has no prior criminal history, according to court officials.
The Salt Lake Tribune initially reported the name of the 15-year-old in an effort to help police locate him. However, after the teen's arrest, and consistent with the newspaper's policy of not naming juvenile criminal suspects, his name is now being withheld.