In 2008, an explosion in Zagreb outside the offices of Nacional, the Croatian weekly magazine, immediately killed two staffers, including the publication’s founder, Ivo Pukanić.

The explosion came from a motorbike parked next to the journalist’s car — an assassination Croatian prosecutors say was planned by organized crime figures from across the Balkans.

A Croatian court convicted six men of the murder, including Slobodan Ðurović, named as a “key middleman” by the court. Interpol and other agencies identified Ðurović as a major international crime figure known as “The Cardinal,” ICIJ partners report.

But while prosecutors alleged that cash from a mysterious $1.1 million transfer into Ðurović’s personal bank account was used to pay some of the assassins — and Ðurović was sentenced to 23 years in jail — authorities were never able to establish who, exactly, ordered and paid for the murder. The payment came from a company called General Pioneer Inc., based in the British Virgin Islands, where strict corporate secrecy rules made it difficult to determine the beneficial owner.

Now, thanks to documents found within the Cyprus Confidential leak, the company’s owner has been revealed. Reporters from ICIJ partners KRIK in Serbia, OCCRP, and BIRD in Bulgaria identified the owner as Ognian Bozarov, a Bulgarian businessman.

Files from the murder trial and corporate records show that Ðurović was an employee at a Serbian company Bozarov owned, called Karizia DOO, for at least a year before the murder. Ðurović left his role at Karizia three days before Pukanić was assassinated.

These new documents also reveal for the first time that General Pioneer paid Ðurović nearly $400,000 four months before the $1.1 million transfer. (It’s unclear if prosecutors were aware of or investigated the $400,000 sum at the time of the trial, report KRIK, OCCRP and BIRD.)

Throughout his trial — and that of another organized crime member in Serbia — Ðurović maintained that the $1.1 million payment was related to real estate. The fee had been paid, he said on the stand, by his “Bulgarian friends” in exchange for his help filing paperwork to the Belgrade city administration for a land deal, according to KRIK, OCCRP and BIRD. When asked by prosecutors why he was paid such a large sum for a simple task that “everyone could … do,” Ðurović failed to provide a clear answer, ICIJ’s partners report.

The new Cyprus Confidential documents raise questions about whether these business dealings were legitimate, according to KRIK, OCCRP and BIRD.

In a written statement to ICIJ’s partner journalists, Bozarov said he “most certainly did not arrange for [Pukanić’s] murder” and had never threatened or harmed anyone. Bozarov said that any payments made through his companies “were purely for business purposes.”

Ðurović and Bozarov were first linked in early November 2007, when Ðurović transferred Karizia to another Bozarov-owned company. Ðurović used Karizia to apply to the Belgrade Land Development Public Agency for a 99-year lease to a land plot, report KRIK, OCCRP and BIRD.

Documents show Ðurović signed a contract in December 2007 with Bozarov’s BVI shell company, General Pioneer, to help secure an expansion of a Karizia construction project in Belgrade. KRIK, OCCRP and BIRD report. For that task, General Pioneer paid Ðurović an exorbitant fee of $400,000, even though, as ICIJ’s partners report, this expansion simply required paying a higher lease. What’s more, it’s unclear why this payment was made through Bozarov’s second company, General Pioneer, instead of Karizia, where Ðurović continued to be employed.

The terms for a second payment of $1.1 million are outlined in a second contract between Ðurović and General Pioneer, dated September 19, 2008 — supposedly for the same task, KRIK, OCCRP and BIRD report.

But leaked correspondence suggests that this $1.1 million payment was made in a hurry. In an email to a Cypriot financial services provider that helped manage General Pioneer, Bozarov’s daughter wrote that the payment to Ðurović was “extremely urgent” and needed to be sent “tomorrow morning, first thing if possible,” KRIK, OCCRP and BIRD report. Bozarov’s daughter did not respond to a request for comment.

Then, just three days before Pukanić’s assassination, Ðurović resigned as a director of Karizia and left the company. Karizia’s ownership was transferred to a Cypriot firm.

Bozarov did not respond directly to questions about his business with Ðurović, but said any payments from his companies were supported by “valid contractual documentation.”

When KRIK reporters visited the Belgrade construction site, they found it empty, overgrown and littered. More than 15 years after the documents were signed and Ðurović was paid over $1.5 million — supposedly connected to construction on this plot of land — nothing has been built.