Jonathon Adamson, 21, pleaded not guilty to the alleged rape and murder of 16-year-old Washington teen Ben Eastman

Suspect in Rape, Murder of Washington Teen Pleads Not Guilty — as His Mom Remains Jailed

One of the two brothers who stands accused of the rape and beating death of a 16-year-old Washington boy pleaded not guilty to murder and other charges on Wednesday, PEOPLE confirms.

Standing before a judge in Lewis County Superior Court, Jonathon Adamson, 21, of Randle, pleaded not guilty to charges of first-degree murder, first-degree rape, tampering with physical evidence and unlawful disposal of remains in the death of Benjamin Eastman III, Lewis County Prosecutor Jonathan Meyer tells PEOPLE.

Get push notifications with news, features and more.

Ben, also of Randle, was last seen by his father on the night of June 23. His body was discovered five days later in a shallow grave on a remote property, according to the Lewis County Sheriff’s Office and prosecutors in probable cause affidavits obtained by PEOPLE.

Adamson is scheduled to return to court on October 11.

• Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter.

Adamson’s brother, Benito “Benny” Marquez, 16, also of Randle, faces the same charges. Marquez is Ben’s lifelong friend, authorities have said.

Marquez was supposed to appear in court on Thursday to enter a plea of guilt or innocence. His court date was rescheduled for next Thursday after his attorney withdrew from the case, forcing him to find and retain a new attorney, says Meyer.

Adamson’s attorney also withdrew from the case, but Adamson was able to hire another lawyer in time for his court appearance.

Adamson and Marquez were charged July 2 and are being held in the Lewis County Jail on $10 million bail each.

Ben’s last known interaction was communicating with Marquez early on June 24, prosecutors say in probable cause affidavits. Authorities believe he was “lured” into the woods “under the guise of a camping trip,” then attacked by Marquez and Marquez’s older brother, the affidavits state.

Court documents detail a savage attack, according to Adamson’s alleged recollections in a police interview.

After forcing the boy to the ground, the two spent about “20 to 45 minutes” hitting him — and kicking him more than 100 times, Adamson allegedly admitted. At one point, while he was still alive, Ben was sexually assaulted with a stick, Adamson allegedly said.

Image zoom Ben Eastman Ben Eastman/Facebook

To “ensure” he was dead, Adamson and Marquez allegedly struck Ben repeatedly in the head with a large rock, according to the affidavit. Then they stripped off his clothes and buried him, the affidavit alleges.

In addition to the arrests of the brothers, their mother Kindra Adamson, 43, and Adamson’s fiancée, Emma Brown, 20, were arrested earlier this week and charged with rendering criminal assistance to Marquez and Jonathan Adamson after the killing.

Kindra Adamson is being held in the Lewis County Jail on $100,000 bond. Brown was released on Thursday on $100,000 bond.

They are both scheduled to appear in court next Thursday.

Image zoom Ben Eastman and father B.J. Eastman B.J. Eastman/Facebook

PEOPLE’s call for comment to Jonathon Adamson’s attorney was not returned. An attorney representing Kindra Adamson had no comment.

“The brutality in this … I just can’t imagine,” the boy’s father, B.J. Eastman, also of Randle, previously told PEOPLE. “I just hope the Lord put my son’s mind in a safe place.”

“The best way I can honor my son is through love,” he wrote in a July 9 Facebook post, asking well-wishers to “#sharethelove” by being kind to others.

Ben’s family has set up a GoFundMe to help raise money for his funeral and memorial.