JACKSONVILLE, Fla. -

Without handcuffs on and looking rather thin, 13-year-old Cristian Fernandez listened Thursday as attorneys argued whether his first interviews with police can be used as evidence in his murder trial.

The big question in the evidence suppression hearing is whether or not attorneys can use Fernandez's initial interview with detectives after his 2-year-old half brother's death can be shown to the jury.

This is critical because a psychologist, chosen by the state attorney's office to do a psychological evaluation of the boy, found he neither understood his Miranda rights nor what he was doing when he waived them at the time of the police interrogations -- the same conclusion two psychologists chosen by the defense came to.

In closed chambers, homicide detectives testified about Fernandez's interrogation so Judge Mallory Cooper could decide if the evidence can be used in the murder and sexual battery cases.

"This issue has a significant impact on not the murder charge, but the other (sexual battery) charge, because without the statement, the state will probably have significant problems proving their case," said Public Defender Matt Shirk, Fernandez's former lawyer.

BLOG: Cristian Fernandez hearing

Prosecutors subpoenaed the teen's former defense attorneys as witnesses.

"I was surprised and happily excused today," Shirk said.

Shirk was released because he did not meet with Fernandez between March 15, 2011, and June 23, 2011.

"The time period between which the state wanted testimony, my involvement in the case was not during that time period, so I was excused," Shirk said.

Fernandez's new team of private attorneys is working to get the subpoena quashed for the other former lawyers, citing attorney-client privilege.