A few weeks ago one of the world’s richest men was arrested for interrogation in Tel Aviv following an investigation in which the Israeli police drew on the support of criminal justice authorities in the U.S., France and Switzerland. The Republic of Guinea was proud to have played its own part in supporting Israel’s investigation.

While we should never forget a criminal defendant’s presumption of innocence in a case, this case highlights the complexity and global nature of modern corruption investigations. The police action in Israel was only made possible by the painstaking investigation and cooperation of law enforcement agencies around the world. It provided an example of how the anti-corruption mechanism of the OECD convention is supposed to work, but only rarely does.

The reason many of these cases are so difficult to investigate is that criminal activity thrives in the labyrinthine world of global finance and secretive accounting. It becomes more difficult still when its activities can hide behind the protection of highly paid lawyers, accountants and financiers, based in London, New York and Geneva and the protective gloss and embellishment of fancy public relations firms.

As president of a developing country, I have first-hand experience of what it’s like to confront well-resourced corruption. In many cases, the entities involved have more resources than the countries they target and exploit. And in particular, they are able to play major media with ease. As they portray it, corruption is endemic in the developing world, and their clients are just businessmen forced to accommodate a predatory local environment.

But this is deceptive. Unchallenged, corruption can impede economic growth, contribute to political and social instability and prevent progress. Before our first truly democratic election in 2010, corporate and governmental corruption was largely responsible for Guinea’s people being condemned to some of the harshest poverty on the planet, despite sitting on some of the world’s most valuable mining reserves.

Following what was to become a high-profile campaign to confront its past, I was invited by the leaders of the G8 to discuss what lessons could be learned for the wider international community.

I explained how we worked to normalize the environment for investors by focusing on transparency; how we refused to turn a blind eye to past misdeeds; how we introduced a new mining code, and insisted on re-examining the opaque deals signed between mining companies and the military government. What’s more, we published all these contracts online for the world to see and worked to see Guinea accepted as a full and compliant member of the international standard for extractive industry transparency.

But I also explained how fighting corruption was by no means the easy option for a developing-world country and how the odds are too often stacked against those governments trying to do the right thing. Those accused of corruption fight back bitterly, usually doing everything within their power to discredit and undermine any government that has the courage to raise corruption charges.

From the moment we announced we would re-examine contracts, Guinea was subjected to a whirlwind of legal challenges, smears and relentless attacks in the international press, all of which had been carefully prepared by some of the world’s best-known public relations firms, in the pay of companies under investigation. But it got worse. On November 9, 2012, Aissatou Boiro, the Treasury director appointed to impose integrity on flows of money, was tragically gunned down on her way home from work.

As we have learned to our cost, no one but the unscrupulous are winners when corruption is allowed to flourish—not the immediately exploited nations and their hard-pressed and very young populations, neither the genuine investor, their corporate shareholders, nor the markets they distort.

Following the G8 there was a commitment to doing more to collectively support the efforts of Guinea and resource-rich developing countries like us. The U.S. and the EU adopted the Dodd Frank regulations and the EU Accounting and Transparency Directives.

But Western countries need to go further. If developing countries are to stick their necks out in the fight against corruption, Western countries must find ways to make professional services providers as accountable as the corrupt businessmen they enable.

There will always be people determined to flout the law, but by working together the international community can make their activity more difficult and help level the playing field for those who play by the rules.

Mr. Conde became the Republic of Guinea’s first democratically elected president in 2010, running on a reform and anti-corruption agenda. He was re-elected in 2015 with 58% of the vote. He was recently appointed Chairman of African Union. FORBES