UPDATE: Forsyth County Sheriff said missing teen runner Byron Grogan, who had been missing since Monday night, "came back to his house" just after 2 a.m. Wednesday.
Officials are investigating the circumstances surrounding his disappearance.
FORSYTH COUNTY, Ga. – Authorities are trying to re-trace the steps of a 19-year-old UGA student who went missing.
Byron Grogan disappeared Monday night after he left to go running on a trail at Chattahoochee Pointe Park located off Old Atlanta Road around 9 p.m.
His friends say he's familiar with the path there from running cross country.
"He's never run away before, so this is very uncommon, and that what concerns us the most and that it borders the Chattahoochee, and last night when he was running many people who run and cool off go into the river," Forsyth County Sheriff Ron Freeman said.
At 11 p.m., when he didn't return home, his friends and family became worried, so they went to the park to look for him.
"When they came looking for him, at once they found his car parked here and they immediately called 911," the sherif said. His keys were inside.
This launched a massive search where there was a large outpouring of support. May says the Lambert High School graduate was popular and was set to start his sophomore year soon at UGA.
"Very scholastic. He graduated honors and was a real leader of our team. He ran cross country at Lambert High School," said Natalie Leonard, the track coach.
PHOTOS | Crews search for missing 19-year-old runner
Grogan was last seen wearing a yellow t-shirt, red shorts, and running shoes. He is described as a 6-foot-tall white male with brown hair.
If you have seen Grogan or have information on his location, you are asked to call Forsyth County Sheriff at 770-781-3087 or 911.