Updated

A pair of teenage brothers and their father are accusing the parents of a Georgia teen found dead inside a rolled-up gym mat of libel and slander, according to a court filing.

Kendrick Johnson, 17, of Valdosta was found dead in January 2013, inside a mat in the corner of a gymnasium at his high school. Lowndes County sheriff's investigators concluded long ago that Johnson died in a freak accident, saying he became stuck upside down while trying to retrieve a shoe that fell into the upright mat. His parents, Kenneth and Jacquelyn Johnson, insist their son was killed.

No one has been charged with a crime in the case.

The Johnsons filed a wrongful-death lawsuit in January in DeKalb County Superior Court. It names 38 defendants, including three Lowndes County High School classmates.

The lawsuit says the attack on Johnson was spearheaded by two brothers "seeking revenge" after one of them had been in a fight with Johnson and says that the brothers were acting on a "parental command" from their father. The lawsuit also says Johnson's slaying was covered up in a conspiracy involving a host of state and local officials.

The Johnsons' lawsuit seeks $100 million in damages.

Brice Ladson, an attorney for the brothers and their father, called the Johnsons' lawsuit frivolous and said he filed a counterclaim last Thursday. Chevene King, a lawyer for the Johnsons, did not immediately respond to a phone message Monday afternoon seeking comment on the counterclaim.

The Johnsons and people acting on their behalf have made statements on social media and in news media interviews that have included allegations that one of the teenage brothers and others killed Kendrick Johnson and the other was an accomplice, Ladson's filing says. The statements have also alleged that the brothers' father told his sons to kill Kendrick Johnson and participated in a cover-up, the filing says.

The Johnsons knowingly made false statements about the brothers and their father that "injured their reputations, and exposed them to public hatred, contempt or ridicule," the filing says. The family sent certified letters to the Johnsons' lawyers in January and February asking that the statements be retracted, but the Johnsons did not comply, the filing says.

The filing on behalf of the brothers and their father asks for a jury trial and seeks $1 million in compensatory damages, as well as punitive damages and attorney fees. Ladson also asked that the case be transferred from DeKalb County to Lowndes County.