SALT LAKE CITY — A mother and son in Utah allegedly illegally bought and sold dozens of firearms over 18 months, including four semi-automatic rifles that were seized on the U.S.-Mexico border.

Norma Llamas Rodriguez, 46, of Moreno Valley, California, and Carlos Arturo Garcia, 21, of West Valley City, bought at least 48 guns through federally licensed firearms dealers, according to a federal indictment. But neither had a federal license allowing them to deal in firearms.

The indictment charges each of them with one count of dealing in firearms without a license. Llamas Rodriguez is also charged with four counts of false statements in the acquisition of a firearm, and Garcia is charged with two counts of making a false statement in the acquisition of a firearm.

Seven of the weapons were semi-automatic belt-fed tripod mount rifles, which Llamas Rodriguez and Garcia bought for about $7,895 using money orders and then illegally transferred to others.

Agents in Utah for the Bureau of Alcohol, Tobacco, Firearms and Explosives launched an investigation in February 2019 after receiving information from a licensed dealer concerned about a suspicious purchase.

Two of the rifles were shipped to dealers in Murray and Salt Lake City where Llamas Rodriguez and Garcia picked them up. Agents also found that between October 2017 and December 2018, Llamas had purchased 22 AR-15 semi-automatic rifles and four handguns from one of the dealers.

ATF agents also learned that six AR-15 rifles were seized at the Nogales, Arizona, port of entry on a bus entering Mexico from the United States. Four of the guns were traced to Llamas Rodriguez. Records show Llamas Rodriquez purchased the firearms just two days earlier and agents traced two others to purchases she made the previous month, according to the indictment.

In a search of two mobile homes in South Salt Lake, agents found three guns, documentation showing wire transfers to and from Mexico, gun operator manuals and $7,400 in cash, prosecutors say.

Llamas Rodriguez was not at the home but Garcia was and, according to the indictment, told agents his mother was buying the guns for Hispanic men in California and was on her way there with one of the belt-fed rifles.

Llamas Rodriguez, who is in the U.S. on a green card, was arrested in California. She made an initial appearance in U.S. District Court in Salt Lake City where she entered a plea of not guilty.

Garcia, a U.S. citizen, was taken into custody when he went to the federal courthouse Monday. He also pleaded not guilty.

Both were released from custody with certain conditions, including Llamas Rodriguez posting a $100,000 bond, pending trial.