FLORIDA - A nine-year-old girl died on Saturday (Oct 14) after her 325-pound (147kg) cousin sat on her as punishment, US media reported.

Veronica Green Posey, 64, told police officers she had sat on little Dericka Lindsay "for being out of control".

Dericka had complained she could not breathe, and was pronounced dead in hospital after authorities were alerted to a cardiac arrest call at her Pensacola home.

The Pensacola News Journal reported that after standing up, Posey noticed that the girl was unresponsive.

She then called 911 and performed CPR on Dericka.

Posey was arrested and charged with homicide and cruelty towards a child.

Dericka's parents, Grace Joan Smith, 69, and James Edmund Smith, 62, were also arrested and charged with child neglect for failing to report Posey's abuse.

Dericka's mother reportedly told police that she had invited Posey over on Saturday afternoon to help discipline the girl.

Posey allegedly hit the girl with a metal pipe and ruler before sitting on her for about 10 minutes.

After 10 minutes, Dericka complained of breathing difficulties, but Posey did not get up for another two minutes.

Dericka's death has been described by the Florida Department of Children and Families as "appalling".