The family of slain US Border Patrol agent Brian Terry is calling the arrest of one of his suspected killers a "milestone."
Mexican authorities caught up with Leonel Sanchez Jesus Meza on Thursday, about 60 miles south of the Arizona border.
His is the second arrest in the case, and authorities continue to search for three more suspects.
Agent Brian Terry was killed in 2010 during a firefight near the Mexican border.
The investigation into Terry's death exposed the botched "Fast and Furious" gun-smuggling sting.
The fallout from "Fast and Furious" ultimately led to a congressional investigation.
The US House of Representatives found Attorney General Eric Holder in contempt of Congress.