An Irish American doctor died under mysterious circumstances after suffering a severe head injury while vacationing in Mexico.

William Thomas O’Byrne III, 54, an anesthesiologist, was pronounced dead on Wednesday, Feb. 28, at the University of Alabama (UAB) Hospital, where he had been on life support after he was flown back to the U.S., reports.

O’Byrne was reportedly assaulted in Mexico but details on what led to the alleged attack aren’t clear.

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The doctor was on a vacation in Puerto Vallarta with friends, when he was found severely beaten and left for dead in a ditch. His friends found him at a hospital where he was hooked up to a ventilator, and he was later flown back to Alabama.

The account of the incident has not been confirmed by U.S authorities. If any crime occurred, the law enforcement jurisdiction would be in Mexico.

A spokesman at the U.S. Embassy in Mexico City said they are aware of the case, and are gathering information. A statement was released, reading: "We are aware of reports regarding a U.S. citizen injured in Puerto Vallarta, Mexico. Out of respect for the family, we decline further comment at this time."

Aerial view of Puerto Vallarta. Credit: Wikipedia/CC BY 2.5

Aerial view of Puerto Vallarta. Credit: Wikipedia/CC BY 2.5

O'Byrne graduated from the University of South Alabama College of Medicine in 1997. He most recently worked at UAB Hospital, where he was also an associate professor.

Dr. Jason Hall, an anesthesiology resident at Duke, said O'Byrne was a special man.

"Like he was to so many medical students and residents before me, he was my mentor and friend,'' Hall said. "He was a gifted physician trained both in medicine and anesthesiology with fellowship training in critical care. He showed kindness and genuine concern for his patients above and beyond that of other physicians."

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Hall said O'Byrne always demonstrated the utmost respect for his colleagues and co-workers.

"He was loved by many wherever he went, be it UAB, New Mexico, or Vanderbilt,'' Hall said. "His passing is a terrible loss for the medical community, and he will be truly missed. His friendship and advice has comforted and motivated me throughout my medical training, and I can only hope to live up to the example he set for all physicians."