Raleigh, N.C. — Three of four Apex teens accused of killing a friend in 2008 were recently charged with attempting to commit the crime five days before they succeeded, according to court documents.

Each of the four -- Allegra Rose Dahlquist, Ryan Patrick Hare, Aadil Shahid Khan and Drew Logan Shaw -- faces one count of first-degree murder for the death of Matthew Josiah Silliman, 18, a student at Apex High School.

Hare and Shaw were also indicted on one count of conspiracy to commit murder.

Wake County deputies found Silliman's body on Dec. 2, 2008, at an unoccupied property in New Hill owned by members of Dahlquist's family. Silliman was reported missing on Nov. 26, and he was the subject of a Silver Alert. Arrest warrants said the homicide occurred Nov. 30.

Dahlquist, Hare and Kahn now face additional charges of attempted first-degree murder and conspiracy to commit murder for an incident on Nov. 25. No details about that incident were immediately available Thursday.

Lawyers for Dahlquist, Khan and Shaw have indicated that the trio would testify against Hare in the murder case.

The case is expected to go to trial May 24.

According to search warrants in the case, three of the accused confessed to their involvement in Silliman's death and implicated the fourth suspect as being directly involved in his death.

The suspects are believed to have been friends with Silliman. Dahlquist and Khan were seniors at Apex High School at the time, while Shaw was a sophomore at Panther Creek High School. Hare withdrew from Panther Creek High School in February 2008.