The Las Vegas coroner investigating the death of AFL player John McCarthy says the Port Adelaide midfielder fell more than nine metres from the rooftop of a casino property.

Clark County coroner Mike Murphy has confirmed to the ABC that the 22-year-old Australian was found at 5:37am (local time) on Sunday and was pronounced dead less than an hour later.

McCarthy's body has been formally identified by a family representative.

Mr Murphy says McCarthy's death is still under investigation, but it appears he fell just over 9.1m from the rooftop of a building at a famous hotel and casino, The Flamingo.

An autopsy has been carried out, but Mr Murphy says toxicology tests may take weeks.

Police are interviewing witnesses and reviewing security camera footage and are expected to release more information shortly.

Jose Hernandez from the Las Vegas Metropolitan Police Department says the Violent Crimes Section has been called in to investigate.