At the time of the murder, the Salvadoran newspaper Contrapunto reported Brown was attacked by eight to 10 people on a coffee farm in San Isidro while driving a rental car with his wife. He was shot five times in the head and shoulder.
The newspaper reported his wife was injured in the attack, but survived. The newspaper said the two were visiting from the United States.
A Salvadoran court issued an arrest warrant for Aquino-Torres in January.
ICE said Enforcement and Removal Operations officers arrested Aquino-Torres at her Ogden home in March. She was placed into removal proceedings and an immigration judge ordered her removed from the United States in July.
"ICE has teams dedicated to locating and arresting aliens wanted for prosecution in foreign countries," said Thomas Feeley, field officer for ERO in Salt Lake City.
"Foreign fugitives are mistaken if they believe they can hide in the U.S. to escape justice in their home countries," he added.
Since Oct. 1, 2009, ERO has removed more than 720 foreign fugitives sought in their native countries for serious crimes, including kidnapping, rape and murder.