Florida A&M University drum major Robert Champion was beaten so severely and by so many people that prosecutors say it was difficult to determine exactly who is responsible for his death during a hazing ritual last year.

His death is not linked to one sole strike but it is attributed to multiple blows, said State Attorney Lawson Lamar at a news conference announcing the hazing charges against 13 people allegedly involved in the beating that killed Champion, the Associated Press reported.

Champion, a 26-year-old FAMU drum major and native of Decatur, Ga., died of internal bleeding from injuries suffered last fall in the beating, which was allegedly given to him on a charter bus in Orlando because he dropped his baton.

Because of the amount of individuals involved and the number of blows the FAMU drum major suffered, it made it tough for investigators to determine who initiated the blow that killed him and therefore the more serious charges such as murder or manslaughter could not be filed in the hazing case.

Those charged in the case face a maximum of six years in prison if convicted.

Champion's mother, Pam Champion, said she was dissatisfied with the charges, although she understands why more serious charges could not be filed.

I was very disappointed in hearing what the charges would be ... but [prosecutors] did explain to me the reasoning behind that, she told CNN's Anderson Cooper.

Pam Champion said murder or manslaughter charges would have been more appropriate.

Hazing in itself is a very light term as to what it is, she said. I don't look at it as being a form of bullying. Hazing is a very brutal assault.

While Lamar said his office did not have the evidence to file harsher charges, one law expert said he missed an opportunity to send a stronger message.

The prosecutor in this case had an opportunity to do something, to send a stronger message, a deserved message based on the conduct, Tamara Lave, a professor at the University of Miami School of Law, told AP.

Champion's death highlighted the problems of university hazings and led to Florida Gov. Rick Scott calling for an investigation into FAMU that led to four students being dismissed and FAMU marching band director Dr. Julian White being fired, the Miami Herald reported at the time.

FAMU's marching band is one of the most storied ensembles in the country. Champion's family wants the marching band dissolved in light of his death, the Atlanta Journal-Constitution reported.