VALDOSTA, Ga. -

A Georgia family is demanding a new investigation into their son's death after a new independent autopsy report confirms their fears that their son, Kendrick Johnson’s death was not an accident.

In January, Johnson was found upside down, rolled up in a 6 foot tall wrestling mat at his Valdosta high school.

The initial autopsy said the 17-year-old died from potential asphyxia. Investigators called it an accident, but the new report suggests that someone may have harmed Johnson.

The family wants justice and they say this new autopsy result proves that their son’s death was not an accident, and they want the investigation into his death re-opened.

It's a battle Kenneth Johnson and his family are determined to fight. They're now taking their concerns to the federal level, in hopes of finding out what really happened to their son, Kendrick.

"If they don't come in, they 're only sending a message to the world: You can kill as long as you can get away with it. That's what they are saying. These people killed my son and they don't want to come in, investigate the sheriff and do what they have to do,” said Kenneth Johnson.

Investigators say Kendrick was reaching for one of his shoes that got stuck in the mat when the accident happened.

An initial autopsy report says he accidentally suffocated from his own body weight and investigators considered his death an accident.

The Johnson family hired Forensic Pathologist William Anderson to perform a second autopsy. Anderson determined Kendrick's cause of death was unexplained, non-accidental, blunt force trauma to the neck.

"I've never had a case, that I can recall, where the prosecution actually was told that this may well be a homicide, the prosecution being the state the police and so forth, and then didn't bother prosecuting it. It's mystifying," said Forensic Pathologist William Anderson.