A 49-year-old migrant from Mexico who was in Customs and Border Protection custody died Monday at an Arizona hospital, according to a statement from the agency released Tuesday.

"U.S. Customs and Border Protection is saddened to report a 49-year-old man from Mexico was pronounced deceased Monday morning in a Southern Arizona hospital," the agency wrote. "Our condolences are with his family."

The man, who has not been identified, was apprehended by Tucson Sector Border Patrol agents at 1 p.m. Sunday south of Casa Grande, according to the statement. While he was being processed, the statement added, "it was determined the man needed medical attention and was transported to a Tucson area hospital."

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The statement said that after the man arrived at the hospital, medical officials determined that he had a pre-existing heart condition. He was reportedly pronounced dead at approximately 9 a.m. Monday.