The judge in Austin Sigg's murder trial agreed Thursday to allow testimony from an expert on the difference in brain function between adolescents and adults.
Marie Banich, Ph.D. is a professor of Psychology at the University of Colorado Boulder. Dr. Banich has not examined Sigg and will not testify specifically about him.
While questioning Dr. Banich, prosecutors said the defense is going to introduce "evidence of trauma" at the trial.
Sigg, 18, is scheduled to go on trial in October in the kidnapping, killing and dismemberment of 10-year-old Jessica Ridgeway and an attack on a female jogger at Ketner Lake.
Sigg has pleaded not guilty to all charges.
Sigg appeared in court Thursday wearing an orange jumpsuit and glasses. He smiled and waved to family members as he entered the courtroom, 7NEWS Reporter Amanda Kost said.
Members of Ridgeway's family wore purple, Jessica's favorite color, to Thursday's hearing, Kost reported.
Additional objectives listed for Thursday's hearing include the request for a change of venue and several motions regarding the jury selection.
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