(Riverton, Wyo.) – The 16-year-old who allegedly robbed a woman in the Walmart parking lot using a pellet gun on Nov. 10 pleaded not guilty this morning in Wyoming’s Ninth District Court.

Adrian Joseph Sixfeathers of St. Stephen’s has been charged with Aggravated Robbery, a felony punishable by five to 25 years in prison. He is being charged by the Fremont County Attorney’s Office as an adult. Sixfeathers is being held on a $100,000 cash bond.

He has two adult co-defendants, Curtis Oldman, 27, and Tiesha Underwood, 22, both of Lander. Oldman has been charged with Conspiracy to Commit a Felony and Accessory before the Fact. Underwood is charged with Conspiracy to Commit Aggravated Robbery and Aiding and Abetting Aggravated Robbery. They both are being held on $50,000 cash bonds. Underwood has been bound over to district court as well, and Oldman will have his preliminary hearing in Riverton Circuit Court next Wednesday.

Underwood also pleaded not guilty this morning.

Judge Norman E. Young set Sixfeathers’s and Underwood’s trials to be held together on March 10, 2014. The trial is stacked behind four other cases.

Oldman’s case is still in Riverton Circuit Court, Deputy County Attorney Pat LeBrun said, noting that his preliminary hearing had been continued to another date.

“On or about November 10, 2013, an emergency call from the Wal-Mart store in Riverton alerted that a male suspect had just recently pointed a gun at a female’s head in the Wal-Mart parking lot,” states the affidavit in the cases. “The caller also reported that the male suspect had stolen the female victim’s purse.”

Read more background on the case in this story.