Sylvester Stallone may be charged with possession of illegal substances, believed to be human growth hormones, after his hotel room and private plane were searched.

Sylvester arrived in Australia on Friday for the country’s premiere of Rocky Balboa but an observation by customs officials in Australia during a routine x-ray caused the actor and his entourage to be detained, causing them to miss the film screening.

Substances were seized during the airport search and on Monday, just before officials arrived to search his hotel room at the Park Hyatt hotel, Sylvester and his team were reportedly seen throwing things out of the windows of the room.

A spokesperson for the Australian Customs Service Richard Janeczko told Sydney’s Daily Telegraph that illegal items had been seized but refused to give details.

A second spokesperson added: “There is a range of options we can pursue in these circumstances. The investigation is ongoing, and we are aware of Mr. Stallone’s travel movements. The material has to be identified, and we have to look at all the options and the evidence before deciding what action to take.”

Sylvester was allowed to leave the country to return to the US on Monday but the investigation will proceed. If found guilty, those in possession of the items could face fines up to AUS$110,000 or five years in jail.