HARLINGEN, Texas (ValleyCentral) — A Harlingen man pleaded guilty Wednesday to smuggling a gun linked to the deadly kidnapping of U.S. citizens in Matamoros, federal authorities said.

Roberto Lugardo Moreno Jr., 42, pleaded guilty to the aiding the smuggling of firearms into Mexico, knowing it was intended for members of the Gulf Cartel, the U.S. Attorney’s Office announced.

It was learned from Mexican authorities that a pistol purchased by Moreno on Oct. 17, 2019, was linked to the March 3 Matamoros incident. A criminal complaint stated the weapon used in the attack was a Diamondback AR-15-style pistol.

“The investigation revealed that Moreno had obtained the firearm at a pawn shop in Brownsville,” the release stated. “Moreno admitted to purchasing the firearm on behalf of another person he knew was going to provide it to a Gulf Cartel figure in Mexico.”

On March 3, gunmen kidnapped four U.S. citizens from South Carolina who traveled to Matamoros to buy medicine before being caught in a shootout.

“Shortly after crossing into Mexico, unidentified gunmen fired upon the passengers in the vehicle.  All four Americans were placed in a vehicle and taken from the scene by armed men,” Oliver Rich, Special Agent in Charge of the San Antonio FBI office Texas, which includes Brownsville, said in the release.

The bodies of Shaeed Woodard and Zindell Brown, of South Carolina, were found in a wooden shed a few miles outside of Matamoros.

The surviving victims, Latavia McGee and Eric Williams, were transported to a hospital in Brownsville.