Speaking to journalists in Baku on September 8, the Ukrainian president said the investigation into the alleged poisoning in September 2004 was "one step away from the active phase of solving this case."
Yushchenko's statement came as Ukraine's prosecutor-general, Oleksandr Medvedko, announced that investigators had determined the time, place, and circumstances in which the poisoning attempt took place.
All that remains, apparently, is to find the individual, or individuals, responsible. Dioxin Poisoning
Austrian doctors responsible for examining Yushchenko several months after the poison was reportedly administered said the Ukrainian politician had ingested a concentrated dose of dioxin.
If investigators have in fact traced the time and place of the poisoning, it would mark a significant development in a seemingly stagnant case.
The powerful toxin caused bloating and pockmarks on Yushchenko's face, giving his skin a greenish hue and adding a macabre note to a tumultuous political season culminating in the mass Orange Revolution protests in December 2004.
Prosecutor-General Medvedko, confirming earlier allegations, said tests on the dioxins found in Yushchenko's blood showed they were highly purified and manufactured in either Russia, the United States, or Great Britain.
He declined to divulge other details. If investigators have in fact traced the time and place of the poisoning, it would mark a significant development in a seemingly stagnant case. Intrigues And Disinformation
The mystery began on September 6, 2004.
Yushchenko, the pro-Western presidential candidate facing off against the Kremlin's preferred nominee, Viktor Yanukovych, became violently ill, suffering severe abdominal pain and facial lesions.
When he was rushed four days later to Vienna's Rudolfinerhaus clinic, his liver, pancreas, and intestines were swollen, and he was barely able to walk.
Doctors were initially baffled. But Yushchenko's supporters already had a theory: that the candidate had been poisoned during a dinner September 5 with Ihor Smeshko, the head of Ukraine's Security Service, at the summer home of Smeshko's deputy, Volodymyr Satsiuk.
Later that month, many were surprised to read a Rudolfinerhaus press release stating doctors did not believe Yushchenko had been poisoned.
But several days later, officials at the Vienna clinic publicly objected, insisting the press release was a forgery -- an episode that conjured up images of a Soviet-style disinformation campaign. An Easy Target?
By December, doctors had confirmed that dioxin was behind Yushchenko's ailment, and that he had received the substance from a perpetrator who allegedly intended him harm.
Yushchenko's supporters immediately pointed to Yanukovych as the likely suspect, and accused Moscow of providing the dioxin.
The Yanukovych camp vigorously denied the charges. Some questioned whether there was in fact any real evidence to suggest Yushchenko had been poisoned.
At the peak of the Orange Revolution protests in December, Yushchenko announced he would soon have proof his opponents had attempted to assassinate him. The proof, however, never materialized. No Conclusions
Since then, an investigation by the Ukrainian Security Service and Prosecutor-General's Office has been under way. But no findings have been announced.
In the interim, many Ukrainian and Western observers have begun to express doubt the case would ever be solved.
Some questioned why it was taking so long to discover the truth -- especially when Yushchenko himself was offering frequent assurances a solution was around the corner. Was the investigation being blocked? Or have investigators simply been unable to build a solid case?
A member of the investigative team told RFE/RL that in such a high-profile matter as the Yushchenko poisoning, it is prudent to wait until the evidence is so watertight that there is no way the case can be thrown out of court.
But many of Yushchenko's supporters believe that with Yanukovych now in the prime minister's post it is unlikely the case will be solved soon -- if ever.