Credit: ABC News.

The investigation continues into the Jet Ski accident that reportedly left Usher's 11-year-old stepson, Kyle Glover, brain dead.

Sgt. Mike Burgamy of the Georgia Department of Natural Resources told ABCNews.com today that the accident was still under investigation, and that the lead investigators had yet to talk with the district attorney's office. Glover's prognosis will determine how they proceed.

"I don't know what's going to happen with the 11-year-old," Burgamy said. "We're going to have to see what his condition is going to be before we present findings of the case."

Jeffrey S. Hubbard, 38, a friend of Usher, a seven-time Grammy winner, and Usher's ex-wife, Tameka Foster, are at the center of the investigation. "He was interviewed, and it's possible he may be reinterviewed," Burgamy said. Attempts by ABCNews.com to reach Hubbard were not successful.

Hubbard was driving a Jet Ski that collided with an inner tube holding Kyle and an unidentified 15-year-old girl on July 8. The two were airlifted to an Atlanta hospital, where Kyle still remains.

Burgamy said Kyle was hit in the head and did not respond at the scene. He was found faceup in water; the unidentified girl was found facedown. The girl sustained a broken arm and a laceration to her head, according to ABC News affiliate WSB.

Burgamy said neither drugs nor alcohol is believed to have played a part in the accident.

Kyle is Foster's son with Atlanta TV executive Ryan Glover. Usher and his ex-wife made headlines this year amid a bitter custody dispute over their two children. But Friday's accident has brought them together, according to the celebrity-tracking website TMZ, which said Usher had chartered a plane for Foster, who was out of town at the time of the accident, so she could be at her son's side.