Brian Smith, of Omaha, collapsed late Saturday night on the campus of the University of Puerto Rico.
Smith was taken to a San Juan hospital, where he was pronounced dead on arrival. Authorities say they do not yet know the cause of Smith's death, but foul play is not suspected.
Puerto Rico newspaper El Nuevo Dia is reporting that Smith had earlier complained that he was not feeling well, and that shortly before midnight fell and hit his chin.
A police report obtained by the newspaper says that Smith under treatment for anxiety problems and took the antidepressant Effexor.
The student group had arrived in Puerto Rico on Thursday night. Saturday morning, the group had a dive near a beach in San Juan.
One of the three professors leading the tour, Larkin Andrew Powell, says that Smith had enjoyed the trip until his death. "We went to a cave, and saw bats and snakes," Powell told the Nuevo Dia. "Even before that we would get to Puerto Rico, Bryan talked about how it wished to see the cave, and they enjoyed it very much. He had a good day."
Smith graduated from Creighton Prep in 2006. He was among 19 students who traveled to Puerto Rico last week with associate professor Larkin Powell to study the ecology of the region.
Smith's family is arranging to bring his body back to Nebraska.
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