Athens, GA– The GBI is conducting an autopsy to find out the cause of death of a man who died after taking a breathalyzer test. Athens Clark County Police officer Mark Sizemore says John Mardsen was taken into custody for driving under the influence and was able to give one sample. After he tried giving the second, Mardsen collapsed. He was taken to the Athens Regional Medical Center where he was later pronounced dead. The GBI still has not announced what was the cause of death.