The navy said it caught Salvador Alfonso Martinez Escobedo on Saturday in Nueva Laredo.

He was presented to the media with alleged accomplices in the Mexican capital Monday.

Martinez Escobedo is suspected of being behind the slaughter of 72 foreign migrant workers in August 2010 and American David Hartley on a lake on the Texas border in the same year.

"Today was a complete, out-of-the-blue shock for me," Tiffany Hartley - David's widow - said. "I hadn't heard any news for 10 months now. So, my life was not expected to have this turn. We always have to be hopeful in that this will move forward to him being prosecuted or David's remains being found - to finding some closure. It's hard to have that, but at the same time, we're hopeful."

The Zetas are known for their ruthlessness and are behind some of the worst atrocities of Mexico's drug war.

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