CHEYENNE, Wyo. (AP) - A former county fire chief awaits sentencing on 10 felony charges that he took minors across state lines and sexually molested them.

Gary Scott faces between 17 years and 22 years in federal prison when he's sentenced May 6 by U.S. District Judge Clarence Brimmer of Cheyenne. Scott also faces possible fines of up to $2.5 million.

Scott, a former Campbell County fire chief, originally had faced 12 federal charges. Assistant U.S. Attorney James C. Anderson said after last week's plea hearing that the other two charges were dropped when Scott could not differentiate between various instances of illegal sexual activity.

Scott's guilty pleas cover sex offenses against three minors that occurred between November 2000 and May 2006.

Anderson said he believed there were more victims. But he said the ambiguity in facts and timelines prevented him from bringing more charges.

"In the federal system, for an individual to plead guilty, you have to admit to the facts in the charge," Anderson said after the hearing.

"It became apparent because of the nature and the scope and the extent of the number of children he had victimized, he could simply not remember (the facts)," Anderson said.

After pleading guilty to each charge, Scott explained how he committed the crimes. Scott said he had taken advantage of minors while on trips to conferences where he was an educational instructor. He said the assaults occurred in Utah, North Dakota, Wisconsin, South Dakota, Virginia and Canada.

Anderson said he expected more details of the crimes will emerge at sentencing.

Cheyenne lawyer Terry Harris represents Scott. Harris declined comment.

Scott told Brimmer that he had decided on his own to plead guilty.

"These charges that are in the information are of course serious charges," Brimmer said. "This could result in a minimum of 20 years and possibly more under these sentencing guidelines. It looks to me like you can do big time."

Scott has been jailed in Scottsbluff, Neb., since Jan. 12.