The parents of a Fresno State University equestrian team member who died after falling from a horse have filed a $10 million negligence claim against the school, saying their daughter was put at risk by the school's lack of coaches or supervision.

In addition, the parents say they are "very concerned" about apparent discrepancies in university reports about their daughter's death.

Shana Eriksson, 18, spent three days in a coma and then died last September after her horse spooked, whirled around and then fell on her during a trail ride with two teammates.

The university maintains the accident was unrelated to any team activity and that Eriksson was riding at her own risk.

University officials said late Monday that they had only seen an informal copy of the claim and were not prepared to respond.

The claim comes on top of a recent admission that an assistant coach injected two horses with tranquilizers at competitions Nov. 22 and Feb. 21. The university said Monday it had not violated any rules but would stop the practice anyway.

The NCAA doesn't have rules about drugging horses at equestrian competitions. But U.S. Equestrian, whose rule book has become the definitive guide to equestrian competition, bans the use of tranquilizers before competitions.

So does state law, because, "simply put, performance-enhancing drugs alter the performance of the animal," said Steve Lyle, spokesman for the California Department of Agriculture.

Violators are required to forfeit any awards and ribbons and pay a $50 fine.

But Lyle said it's unclear whether the state laws apply to college events, and the agency has decided not to take action. Lyle said his agency will, however, rewrite the regulations to clarify whether the rule applies to college events.

Sherril Evans, whose twin daughters ride on the team, said she's very concerned about Shana Eriksson's death and the use of tranquilizers.

"There's a huge ethical dilemma here," she said. "What in the world kind of message are we sending our kids?"

In their claim filed against California State University, Eriksson's parents accuse the university of failing "to provide adequate coaching, instruction or supervision" of their daughter by allowing her to go on an unsupervised trail ride.

The all-female team, the largest in the country with close to 100 riders, is a significant piece of the university's efforts to comply with Title IX gender equity requirements, balancing male athletes in the marquee sports.

Although the equestrian team had begun practicing at the time of Shana's accident, no coaches had been hired.

Shana's mother, Karan Eriksson, said that while looking into her daughter's death, she was "disconcerted" to find several versions of university incident reports, some of which exclude information that could cast a poor light on the school.

Responding to a California Public Records Act request, the university provided hundreds of pages of internal reports to Associated Press, which include several discrepancies about the riding conditions and the ambulance response times.

Shana Eriksson spent three days in a coma before her death. The Fresno County Coroner's office has not released its report, saying that the investigation is still open.