SALT LAKE CITY — Three people arrested as part of the largest crackdown on Native American artifacts trafficking entered guilty pleas Friday in federal court.

Joseph M. Smith and his wife, Meredith Smith, Tad C. Kreth and Reese G. Laws were preparing to go trial in May after prosecutors turned up the heat on them with an amended indictment alleging 38 felony counts of trafficking in archaeological resources, theft of tribal and government property and conspiracy. They originally faced a total of 27 counts.

Joseph Smith's attorney, Ben Hamilton, believed the government overvalued the allegedly stolen artifacts in order to pile additional felony charges on the four. Smith faced all 38 counts because the sales of the items to an undercover informant took place in his Blanding home.

"We believe they inflated the value on every item except for one," Hamilton said.

That one — a turquoise pendant — led Joseph Smith, 33, to plead guilty in U.S. District Court to one count of trafficking in stolen artifacts. Prosecutors agreed to drop the other counts. Smith also must forfeit any Native American artifacts he has in his possession.

"I believe it's a fair resolution," Hamilton said.

Meredith Smith, who was in the home during the sales but not a participant, initially faced six charges. She and prosecutors reached a diversion agreement that will dismiss the charges if she commits no crimes in the next six months.

Also Friday, Kreth, 32, pleaded guilty to one count of trafficking in stolen artifacts. He sold a piece of sandstone shaped into a foot. Prosecutors agreed to drop 16 other counts and recommend he be placed on probation.

Laws, 29, pleaded guilty to misdemeanor theft of government property. Prosecutors agreed to drop eight other counts and recommend probation.

Judge Ted Stewart will sentence Laws, Kreth and Joseph Smith on July 18. Stewart is not bound by the prosecution's recommendations.

The four defendants in court Friday were among 25 Utah, Colorado and New Mexico residents arrested in 2009 after a two-year sting operation in the Four Corners area. A confidential informant, Ted Gardiner, bought 256 Native American relics for a total of $335,685 during that time. Gardiner and two defendants — James D. Redd and Steven L. Schrader — committed suicide after prosecutors filed criminal charges.

To date, none of the defendants have gone to trial. More than half pleaded guilty to reduced charges and were placed on probation.