Terry was killed almost seven years ago on December 14, 2010, in a gunfight between five cartel members and border control agents.
A man who allegedly shot and killed a Border Patrol agent in Arizona several years ago was reportedly arrestedin Mexico on Wednesday.
In his plea agreement, Osorio-Arellanes agreed the shot that killed Terry was sacked by a member of his group, although he did not claim to have personally fired the shot or blame someone else specifically for the crime.
Four others have already been tried and convicted in connection with Agent Terry's murder. During this operation, the ATF was allowing known drug cartel members to buy firearms in Phoenix and Southern Arizona. Terry's elite Border Patrol unit attempted to arrest the men when the gunfight broke out, leading to Terry's death. Two men have so far gone to trial and been sentenced to life in prison.
Kelly said the latest arrest illustrates the commitment of the administration to seek justice.
Mexican authorities arrested a man suspected of shooting dead a U.S. border guard in 2010 and aim to extradite him to the United States, prosecutors said today.
That's a mountainous region noted for drug activity. Later, Holder admitted that "there may be a situation here in which a serious mistake was made, and if that's the case then we'll find out and we'll hold somebody accountable".
The statement didn't identify the suspect by his full name, but a Mexican federal official confirmed it was Heraclio Osorio-Arellanes. The official spoke on condition of anonymity because he was not authorized to comment officially.
Verza reported from Mexico City.
The suspect is due to be tried in the U.S. District Court for the District of Arizona for crimes including homicide, conspiracy and drug trafficking, the office added.
US officials had offered a $250,000 reward for information leading to the arrest of Mr. Osorio-Arellanes.
Mexican authorities said Thursday they've arrested one of the fugitives wanted on murder charges in the death of Border Patrol Agent Brian Terry - a shooting that drew new attention to the unsafe border and exposed a botched Obama administration gun crimes probe. Four members of the group were arrested, and two assault rifles were found at the scene.
Warmer weather moves in again for the holiday weekend
There may be some sunshine around over the Easter Weekend , but any sun we do see will primarily come early in the day. Eventually, clouds should clear out during the overnight period with temperatures in the 40s.