Raleigh, N.C. — Slain Apex teenager Matthew Silliman likely died from asphyxiation and was beaten with a hammer, according to search warrants unsealed late Wednesday.

Deputies found the 18-year-old's body on Dec. 2 at a mobile home at 4221 Olive Branch Lane in New Hill after receiving a tip from Apex police.

Allegra Rose Dahlquist, 17, of 601 Walcott Way, Cary; Ryan Patrick Hare, 18; of 100 Walnut Hill Court, Apex; Aadil Shahid Khan, 17, of 901 Bristol Blue St., Apex; and Drew Logan Shaw, 16, of 107 Woolard Way, Apex, were indicted Tuesday on one count of murder in the case.

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

According to the warrants warrants, one of the accused confessed to being involved in Silliman death and implicated three others. Of the other three, two more confessed to their involvement. The three who confessed implicated the fourth suspect as being directly involved in his death.

One of the suspects admitted to beating Silliman on the head with a hammer, tying him with zip ties, suffocating him with duct tape and disposing of him in a plastic bag, the warrants stated. The suspect also told investigators they tried to use medication commonly used for animals to plan the crime.

The assailants also read Silliman's fortune to him off tarot cards before his death, the warrants stated.

Silliman, an Apex High School student, was reported missing Nov. 26 and was the subject of a statewide Silver Alert. According to arrest warrants, the homicide occurred Nov. 30.

Wake County real estate records say the property where Silliman was found belongs to Dahlquist's family.

Authorities have said little about the case, but Silliman's page on Facebook, an online social networking site, lists the suspects as his friends.

Dahlquist and Khan are seniors at Apex High School, a Wake County schools spokesman said. Shaw is a sophomore at Panther Creek High School in Cary. Hare withdrew from Panther Creek in February.