(CNN) -- A state medical examiner will try to determine the cause of death of two University of Florida students who died over the weekend while exploring a cave in northwest Georgia.
Michael Pirie, 18, and Grant Lockenbach, 20, both died Saturday of what appears to be hypothermia, David Ashburn, director of Walker County emergency services, said late Sunday. Autopsies will be conducted, he said.
"Both passed away in Ellison's Cave in Walker County and their bodies are at the state medical examiner's office now," Ashburn said. "We think Grant went down first and Michael went down to help him."
Their bodies were removed from the cave late Saturday, he said.
They were part of a group of five guys and five girls who were exploring the Crockford-Pigeon Mountain Wildlife Management Area in LaFayette, Ashburn said.
Walker County Sheriff Steve Wilson said affiliate WTVC that Pirie and Lockenbach broke away from the group and decided to explore by themselves.
"They were only dressed in T-shirts and jogging shorts and certainly were not dressed appropriately for going in a cave," Wilson said.
Other members of the group were able to communicate with the men for up to 45 minutes, but their voices eventually grew faint and disappeared.
Lockenbach was president of the Fellowship of Christian Athletes, which held a prayer service for the two students Sunday night, the Orlando Sentinel reported. Pirie was also a member of FCA and played in the University of Florida Drumline.