LISBON – The crash that killed 12-year-old Ashlee Stone Wednesday evening was caused by speed and an overloaded sled, according to District Game Warden Rick Stone. The wreck remained under investigation Thursday.

The girl, who was operating the 2005 Arctic Cat 660, was killed instantly when the sled struck a tree head-on.

According to Warden Stone, who is not related to the victim, Ashlee Stone had the throttle fully open when the sled crashed. She hit the handlebars with her chest and catapulted over the bars into the tree. The nose of the sled slammed into the tree, with the skis resting on either side of the trunk, he said.

The high-speed crash occurred at the end of a 60-yard straightaway, the warden said.

While operating the sled, Ashlee Stone was sitting 6 to 10 inches from the handlebars to make room for her two passengers, a 10-year-old boy and a 13-year-old boy. The names of the boys, who are not related to the girl, were not released because of the ongoing investigation into the circumstances of the crash.

According to Warden Stone, Ashlee Stone decelerated the sled just as she approached a crest of a hill and then suddenly accelerated. She may have confused the throttle with the brake, he said.

The three children were out for a ride on a trail along a power line, and crashed just 200 yards from Ashlee Stone’s home. According to Inland Fisheries and Wildlife spokeswoman Deborah Turcotte, all three were wearing helmets that fit securely on their heads.

“This was Ashlee’s first season snowmobiling, her mother told wardens, and she had been riding quite a bit this season,” Turcotte said.

“Inexperience, speed and too many people on one sled” caused the crash, Turcotte said. Warden Stone explained that at the speed Ashlee Stone was traveling, she couldn’t have controlled the machine with the amount of weight it was carrying.

Maine law requires anyone under 10 years old to be accompanied by a parent, unless the land is owned by the parent or guardian, or the parent or guardian has received permission for the youngster to ride there. Any child under 14 may not operate a snowmobile across any public trail maintained for traffic, but the trail Stone was on was not maintained for traffic, so there was no violation of state law in Ashlee Stone’s conduct, Turcotte said.

Ashlee Stone was the daughter of Mandy Stone and Steven Dunigan. The girl was a seventh-grader at Philip W. Sugg Middle School. Her passengers are students in Lisbon schools. Both boys were treated at Lewiston hospitals after the crash for nonlife-threatening injuries.

According to a news release from the middle school, the Lisbon Crisis Response Team is coordinating grief counseling for students through the Lisbon School Department and Tri-County Mental Health Services.

Ashlee Stone was a past student council representative and very active in many clubs and organizations including the Art Club and Civil Rights Club. She received the Presidents Award for Academic Achievement and was on the Sugg school honor list.

Last July, she was among Lisbon students honored for her work with the district’s Junior Volunteer Program, which provides students with an opportunity to volunteer in their community.

At the time, community resource and volunteer coordinator Monica Millhime said that the young volunteers had to maintain good grades, homework assignments, exhibit good citizenship values, follow the guidelines set forth by the volunteer program and keep track of the time they spend volunteering.

In December 2007, Stone was part of a project for sixth-grade students to raise awareness of the benefits of recycling at school, including setting up recycling boxes, and making posters with tips on saving energy and not wasting food.

She attended the Open Door Baptist Church, where she had been recently baptized.

Stone’s death was the fifth snowmobile fatality this season. Since 2000, five juveniles under the age of 15 have died in snowmobile accidents.