AUSTELL, Ga. (June 28) - A teenager was killed at the Six Flags Over Georgia on Saturday when he hopped a pair of fences into a restricted area and was struck by the theme park's popular Batman roller coaster, authorities said.

Local NBC affiliate WXIA reported on it's Web site 11Alive.com that the boy was decapitated around 2:30 p.m. The coaster can travel as fast as 50 miles per hour.

Park spokeswoman Hela Sheth said in a news release the 17-year-old scaled two six-foot fences that were clearly marked with signs that read "Danger" and "Do Not Enter."

"We do not know why this person was intent on gaining access to this restricted area," Sheth said. She did not identify the teenager.

"Some witnesses have stated that the individual was trying to retrieve something he had lost. Others reported that he was trying to touch the ride. This is merely speculation at this point, and we are working with park visitors and local police to learn more."

She said no guests on the ride were injured.

Cobb County police were investigating the incident on Saturday. They did not immediately return a phone call seeking comment.

Three security guards were keeping visitors away from the coaster ride on Saturday.

A teenager's legs were severed when cables snapped on the Superman Tower of Power ride at Six Flags Kentucky Kingdom in Louisville in June 2007. Doctors were able to reattach Kaitlyn Lasitter's right foot, but she had to have some of her left leg amputated and subsequent surgeries.

State officials blame a faulty cable and slow response by an amusement park ride operator in the accident. Her family is suing Six Flags Kentucky Kingdom, claiming the park failed to maintain the ride and equipment and ensure riders' safety. The amusement park has denied liability in court filings.