Ryan Patrick Hare, 19, is charged with first-degree murder. Police have implicated three other teens in the murder: Aadil Shaaid Kahn, 18, Allegra Rose Dahlquist, 19, and Drew Logan Shaw, 18.
Sheriff's investigators found Silliman's body on the bathroom floor of an empty mobile home near New Hill in southwestern Wake County on December 3, 2008. According to the medical examiner, the Eagle Scout was drugged and suffocated.
Hare is accused of being the mastermind behind the plot that ended with Silliman's death. Prosecutors say he was angry about a relationship between Silliman and Dahlquist - who was his girlfriend.
The defense has tried to pick apart the prosecution's case, saying Silliman had attempted suicide in the past, and Hare only took part in an assisted suicide in his December, 2008 death.
As the prosecution continued to present evidence Tuesday, City-County Bureau agent Beth Whitney took the stand for a second day with more information about what she found on computers seized from the homes of all four suspects.
While much of what she said was technical, it was a chat session between Hare and Kahn she read that raised eyebrows in the courtroom. The online conversation took place just a couple of weeks before Silliman's death.
Whitney said Kahn used the screen name, 'AkhanX47' and Hare used the screen name 'F8less shadow'.
In one exchange, AKahnX47 says "It will probably hurt, the parts that cared for him as a friend but, oh well, he has it coming."
"You take my girl, I take your life," he writes later.
Further in the conversation:
F8less shadow: "Do you think anyone would take a girl from me again?"
AKahnX47: "Make Matt dig the hole."
Dahlquist and Khan were classmates at Apex High School with Silliman at the time of his death while Shaw was a sophomore at Panther Creek High School. School officials have said Hare withdrew from Panther Creek earlier in 2008. All of the defendants, except Hare, were under 18 at the time of the alleged murder.
In her testimony last week, Dahlquist testified she had developed a romantic interest in Silliman.
She also said that Hare tried twice to kill Silliman - the first time choking him with a zip tie in late November, 2008. Then - five days later at the empty mobile home owned by Dalquist's family - she says Hare hit Silliman in the head with hammer.
After the blow with the hammer failed to knock Silliman out, Dahlquist said they gave him the option to kill himself. She said Silliman then drank wine laced with horse tranquilizers. After he passed out, Dahlquist said Kahn put duct tape over his mouth. Then, she and hare bound Silliman's hand and feet and put a plastic bag over his head while he was still breathing.
Dahlquist testified as part of a deal with prosecutors that allowed her to plead guilty to lesser charges. She has not yet been sentenced.
Kahn struck a similar deal with prosecutors, but they have since said he will not testify and have asked the judge to scrap the plea agreement.
Shaw has testified without a plea agreement - saying he was not present at Silliman's death and won't take the second-degree murder charge plea offered by prosecutors.