(Oct 28): A major anti-corruption organization has called on Leonardo DiCaprio to "do the right thing" and pay back his earnings from The Wolf of Wall Street, estimated to be worth at least $25 million, should the U.S. Justice Department find that they are linked to a multibillion-dollar 1MDB Malaysian corruption scandal.

"If he knows these are corrupt funds, we would very much like to see him return them," says Samantha Grant of Transparency International, a Berlin-based non-governmental organization that looks to combat global corruption and prevent criminal activities arising from it. "If that money is found by the DOJ to be corrupt, to not give it back sort of says that money that was due to go to the Malaysian public is sitting in Leonardo DiCaprio's account."

On Oct. 18, DiCaprio issued his first statement concerning his ties to those allegedly connected to the scandal, including his Wolf of Wall Street producers Riza Aziz and Joey McFarland, who are co-founders of Red Granite, which funded the Martin Scorsese-directed film, and controversial Malaysian businessman Jho Low.

Coming three months after the DOJ filed its record-breaking seizure complaint, which included over a billion dollars of assets in the U.S. - properties, artwork and even the Wolf of Wall Street film itself, all allegedly financed with money diverted via the 1MDB Malaysian sovereign wealth fund - the statement, the only one so far from celebrities linked to the scandal, sought to assure the public that DiCaprio was working with authorities and support all "efforts to assure that justice is done in this matter."

Claiming to have first heard of the civil action in July, it asserted that DiCaprio "immediately had his representatives reach out to the Department of Justice to determine whether he or his foundation, the Leonardo DiCaprio Foundation (LDF), ever received any gifts or charitable donations directly or indirectly related to these parties, and if so, to return those gifts or donations as soon as possible."

However, while agreeing to return "gifts or charitable donations" is a bold step, it's only a fraction of the allegedly corrupt money DiCaprio may have received. The carefully worded statement may actually cover just a few million dollars, most coming from the sale of artworks on behalf of the Foundation, plus items such as Marlon Brando's best actor Oscar statuette for On the Waterfront, which was presented to the star as a birthday gift by Aziz and McFarland.

But there's also the not entirely small matter of DiCaprio's compensation for Wolf of Wall Street to consider.

The actor is estimated to have earned at least $25 million for his lead role as Jordan Belfort, plus more as a producer on a film that took home almost $400 million at the box office - money that would not be labeled by anyone as either "gifts" or "charitable donations."

From a legal perspective, experts say it would be unlikely that federal law enforcement authorities will pursue such earnings unless they are able to show he knew or should have known that the film's financing was rotten. They point to a doctrine called the "innocent owner defense."

Assuming that DiCaprio didn't knowingly facilitate the laundering of Malaysian public funds - and if he did know, he's potentially facing criminal troubles - he would probably fall under the category of a "bona fide purchaser of value," meaning he rendered typical acting and production services to obtain the millions received for the film. The same goes for others who worked on Wolf of Wall Street, from those on the top of the food chain like Martin Scorsese to those on the bottom like those who guarded parking spots during the production.

Some might wonder whether DiCaprio, because of his close ties with Red Granite's Aziz and McFarland might have been curious about the origins of their wealth and therefore should have known where money was derived. The problem for authorities is the enormous difficulty in proving that the star had good reason to suspect or willfully blinded himself to the strong possibility of tainted money.

It's all dependent on particular facts, says attorney Steven Kessler, a specialist in civil forfeiture, who offers as an example the distribution of proceeds from a bank robbery.

"If you [as the bank robber] have dirty money and go to the newsstand and pay $1 for a copy of the LA Times, the government isn't going to go after the money because it's clear that the vendor wouldn't have known that the money was dirty," he says. "Now, if you were to walk up to him and give him $100 for a pack of gum, and the bill has red powder indicative of a duffel bag that has exploded upon opening, the situation may indicate he should have known."

DiCaprio, who is accustomed to getting substantial sums as an A-list star in Hollywood, has cooperated with law enforcement, according to sources, but investigators may only be probing what he knows about Aziz and others who could be the focal point of potential criminal charges. (Red Granite has itself denied knowledge of receiving illegitimate funding.)

Failing the legal route of seeing DiCaprio's Wolf of Wall Street money returned, there's the moral and ethical aspect, which is where Transparency International is hoping its pressure will have an impact.

As well as urging the actor to repay his earnings, the organization has called on DiCaprio to sign its Declaration Against Corruption, asserting that not only will he not seek bribes, but will work to campaign against corruption and report its abuse.

Grant says that having a figure such as DiCaprio on board - someone who has a "huge influence over government and private sectors and people" - would be a major statement, especially in Malaysia, where Prime Minister Najib Razak, the figure at the very center of the scandal, is still in power and has used his authority to extinguish investigations.

"We live in an very interesting world, so by Leonardo DiCaprio saying publicly that this is not OK, he's actually probably putting more pressure on Prime Minister Najib than maybe even the Department of Justice," she says. "Because the Malaysian people will hear that much more loudly than anything else."

But Grant adds that the move would also benefit DiCaprio himself, especially as he attempts to protect his image as an environmental campaigner from the flames of the scandal and show he'll conduct the necessary checks in the future. Earlier this month, the Bruno Manser Funds rainforest charity suggested DiCaprio should step down from his position as UN Messenger of Peace with a special focus on climate change, directly linking the 1MDB corruption scandal with widespread deforestation in Malaysia.

"Protect yourself by doing the proper due diligence, sign this declaration and say, 'I will not be a part of this,'" Grant says. "It does benefit him. If he had looked perhaps a bit more, if the standard had been a little more 'this is not an acceptable thing to do,' perhaps he wouldn't have the issue of 25 million questionable dollars in his bank account."

DiCaprio's reps have declined to comment on this article.