Usher Stepson's Jet Ski Accident: Friend Probed

A family friend of R&B star Usher is under investigation after the singer's 11-year-old stepson was left reportedly brain dead last week during a jet ski accident while swimming in a Georgia lake.

Jeffrey S. Hubbard, 38, a friend of Usher and his ex-wife Tameka Foster, is now being investigated after the July 8 collision on Georgia's Lake Lanier that caused 11-year-old Kyle Glover and an unidentified 15-year-old girl to be airlifted to an Atlanta hospital, where the boy still remains.

"The accident is under investigation, and Hubbard is [under investigation] as the operator of the personal watercraft," Sgt. Mike Burgamy with the Georgia Department of Natural Resources told ABC News.

"A pontoon was pulling the two adolescents on an inner tube, and the personal water craft went over the top of them," he added. Burgamy said that approximately 20 seconds after the accident occurred Eric Isom, one of two department rangers who witnessed the incident, leaped into the water to assist the two kids. Glover was hit in the head and was unresponsive at the scene. He was found face up in water, and the unidentified 15-year-old girl was found face down, he said.

The girl sustained a broken arm and a laceration on her head, according to ABC News affiliate WSB. Calls by ABC News to Childs Healthcare of Atlanta at Egleston were not immediately returned.

Burgamy said that drugs or alcohol use is not suspected to have been a factor in the accident.

Usher, whose full name is Usher Raymond IV, and his ex Tameka Foster have made headlines this year amid a bitter custody dispute over their two children, but this tragedy has brought them together, TMZ reports. The star entertainer chartered a plane for Foster, who was out of town, so she could race to be at the side of her son with Atlanta TV executive Ryan Glover.

For Usher, the incident is the latest in a string of difficult events.

After the bitter divorce, last month Usher had to call 911 and get a restraining order after a trespasser/stalker incident in which a woman got into his gated community, camped out on his front stairs and rang his doorbell repeatedly.

While now divorced from the mother of his children, Usher recently told ABC's Robin Roberts he takes fatherhood very seriously. "My steadfast belief is that a father is important in a child's life," he said.

ABC News Radio contributed to this report.