BOISE -- On the first full day of Joseph Duncan’s death sentence hearing, the prosecution called numerous witnesses including Steve Groene, the ex-husband of one of Duncan’s murder victims and the father of all three children involved.

Not only was Steve Groene a witness today, he has been in the courtroom listening to testimony for two days -- testimony full of graphic horrific details.

During Groene's testimony the prosecution asked him to identify the hand writing of his two youngest children, through letters those children wrote to him while in captivity -- letters that Duncan never mailed.

Nine-year-old Dylan and 8-year-old Shasta wrote: " I miss you very much. We know what happened to mom."

What happened to their mom, her boyfriend, and their 13-year-old brother Slade is that Joseph Duncan bound and bludgeoned them to death with a framing hammer.

Duncan not only admitted to those crimes but has been extremely forthcoming with information -- volunteering minute details to investigators during an interview several months after his arrest.

Thursday, a Kootenai County detective who conducted that interview took jurors step-by-step through Duncan’s meticulous planning and execution of these heinous crimes.

Duncan told detectives his “primary objective was to take the kids.”

Steve Groene maintained his composure while on the witness stand, but cried during details about the senseless murders of his loved ones.

In afternoon testimony, video from a security camera was shown to jurors.  It is from a gas station in Kellogg, Idaho, just hours before Shasta was rescued and Duncan was captured.

And then the most dramatic evidence of the day -- a recorded conversation between a Coeur d’Alene Police officer and Shasta Groene immediately following her rescue.

"Where's your brother?" asked Officer Shane Avriett.

"He's in heaven. He killed Dylan.  If you look in the back of the truck, there's a gun in there," said Shasta Groene.

"Where's Dylan now?" asked Officer Shane Avriett.

"He's dead.  He hit my brother right there, it was a slug, too. (crying) Then he burned his body," said Shasta Groene.

"There’s been a lot of people looking for you.  What made you guys come (to Denny's) tonight?  Just hungry?" Officer Shane Avriett.

"He was gonna take me home.  He said he was gonna change his mind because I taught him how to love," said Shasta Groene.

Jurors and others in the courtroom cried when the heard Shasta's interview. It was another day of dramatic testimony with more to come.