The sheriff's office says Markeith Kearney, 18, went to a friend's house at 1512 East River Road to swim in a pool with a group of other boys.
A witness told investigators the teens were pushing each other into the pool.
But, investigators say they've learned Kearny entered the pool from the shallow end and was taken off guard by the slope down to the 8 foot deep end.
"He started struggling and they actually thought he was playing. Once they realized he wasn't playing, the adult out there asked one of juveniles out there to jump in to see if they could assist," explained Captain Tim Strickland with the Franklin County Sheriff's Office.
Another teen went in to get him, but had trouble finding Kearney because the water was murky. The pump in the pool was not working, and Strickland said the water was dark green/brown in color.
When the teens got him out, Kearney was unconscious.
Franklin County EMs arrived and took the 18-year-old to Franklin County Regional Medical Center where he was pronounced dead.
"We love him dearly and we know he's in a better place. But we just, it's just a shock the way he left," said Kearney's grandmother Martha Alston.
No charges have been filed and investigators said there would be none unless there was new information from witness interviews.
"It's totally a freak accident. We're not pursuing any charges at this time. I do have a few people I need to interview," said Strickland.
Kearney was a rising senior and played defensive back for the Louisburg Warriors where he was a leading tackler for the team.