MIAMI (CBS4) - The South Florida Marine veteran released from a Mexican prison after a harrowing four-month ordeal is speaking out about his terrifying time behind bars.

Speaking to McClatchy Newspapers, publisher of CBS4 News Partner The Miami Herald, Hammar described the harrowing experience while in Matamoros prison since August 13.

“They threw every threat in the book at me,” Hammar said by phone from his parents home in Palmetto Bay. “They’d cut my head off, they told my family.”

Hammar returned to South Florida on December 24th after driving with his father from the U.S/Mexico border in Brownsviile, Texas.

Hammar, a Westminster Christian graduate, was arrested while trying to cross the border on his way to Costa Rica. Hammar had his great-grandfather’s shotgun on board. He thought he had the proper paperwork, but once across the border, he was immediately arrested, placed in a notoriously dangerous prison some say is run by a drug cartel and charged with bringing a firearm into the country which is a federal crime.

Click Here to read more of his interview with the paper.

(©2013 CBS Local Media, a division of CBS Radio Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed. McClatchy Newspapers & CBS4 news partner The Miami Herald contributed material for this report)