An Australian court will face difficult constitutional issues next month when the government seeks to seize the profits from a book by David Hicks, the former Outback cowboy who spent years as a U.S. prisoner after being captured in Afghanistan.

Hicks, nicknamed the “Aussie Taliban,” spent more than five years at the Guantanamo Bay detention center before returning to Australia to complete a sentence imposed by a U.S. military commission. His book about his experiences has sold more than 30,000 copies.

Australian official said Thursday they will seek to seize the proceeds from the book under a law that makes it illegal to profit from one's crimes. But legal experts say the outcome of the case is uncertain since Hicks was not convicted in Australia, or even in a regular American court.

The experts say the case could force the court to rule on the legitimacy of the military tribunals set up by the United States to try prisoners being held at the Guantanamo Bay facility.