A former inmate of the juvenile detention center in Casper pleaded not guilty Friday to charges in connection with an alleged sexual assault there in March.

Harlan Buddy Taylor, 18, is accused of aiding and abetting first-degree sexual assault and conspiracy. He is being charged as an adult and faces the possibility of between five and 50 years in prison if convicted.

Appearing in Natrona County District Court on Friday for his arraignment, Taylor spoke only to enter his plea and answer procedural questions from Judge Thomas Sullins.

Also charged in connection with the case is 17-year-old Carlos Arellano. He is expected to be arraigned next week and is also being charged as an adult.

The case stems from a sheriff's office investigation into allegations that two inmates, ages 15 and 16, were assaulted in their dormitory-style cell at the center in March.

The 15-year-old told a sheriff's investigator that Arellano and Taylor, who were housed in a cell with him, grabbed him and wrestled him to the floor, where Arellano allegedly sexually assaulted him, according to court papers and testimony by a sheriff's investigator at a court hearing in April.

The 16-year-old also spoke with authorities, and he alleged that Arellano sexually assaulted him in the same cell while other inmates held him. The alleged victim did not implicate Taylor in that instance.

In addition to the sheriff's office, the Wyoming Department of Family Services investigated sexual assault allegations at the center, although state and local officials haven't confirmed whether the investigations are related.

In the state's investigation, the Department of Family Services found that an inmate at the center had been sexually assaulted and that staff and supervisors there failed to report it to the facility's administrators or the state. The investigation also found that the area wasn't staffed properly the time.

Since those allegations, a Colorado company has taken over operations of the center, which is housed on the third floor of the Hall of Justice in downtown Casper. An official with Cornerstone Programs Corp. has said that before the company took over, some high-risk inmates at the center had been housed in dormitory-style rooms, rather than being housed alone.

Taylor remains held at Natrona County Detention Center in lieu of $35,000 bond.

Reach crime reporter Joshua Wolfson at (307) 266-0582 or at josh.wolfson@trib.com.