Three of four people involved in a methamphetamine and stolen firearms investigation following a Casper robbery last week appeared for preliminary hearings in Natrona County Circuit Court on Thursday.

The case of 19-year-old River Walsh will proceed to trial after he waived his preliminary hearing.

41-year-old Maria Jackson entered a not guilty plea to one count of possession of a controlled substance.

In a plea deal, 43-year-old David Burnite pleaded guilty to methamphetamine delivery charges. In exchange for his guilty plea, prosecutors will seek no longer than one year of probation.

A fourth person, 24-year-old Kyle Barrus, was scheduled to appear in district court on Thursday, but his preliminary hearing was rescheduled for next week to accommodate for amended charges.

Prosecutors claim Walsh traded several stolen items to Barrus for methamphetamine. Some of the stolen items, including firearms, were found at a residence Barrus had been staying at.

Further investigation led police to the home of Burnite and Jackson, the alleged methamphetamine suppliers for Barrus.

Barrus was facing several burglary and drug-related charges last week. Trials for Walsh and Jackson will be set for a later date.

Authorities say the case remains under investigation.