Bradley Murdoch, 67, died in jail without disclosing where Peter Falconio's remains might be.
The agency says that they "appear to be pressure vessels from a space launch vehicle".
The 91-storey luxury hotel on the Gold Coast in Queensland was meant to be Australia's tallest building.
The body of Piper James was found in January surrounded by dingoes on the island of K'Gari.
The man allegedly used social media and gaming platforms to target children in more than a dozen countries.
Piper James's body was found on a beach surrounded by dingoes, but a coroner found evidence "consistent with drowning".
The body of Piper James, 19, was found on a beach in Australia on Monday surrounded by dingoes. Officials are investigating her cause of death.
Local police have yet to determine whether the 19-year-old tourist died from drowning after going for a swim or was attacked by the animals.
Footage shows the skydiver stuck on the tail before cutting himself free and continuing with dive.
