And Russian officials said Wada's decision only served to shed doubt on the revelations in McLaren's report.
"In general the information of the McLaren report appears to be incomplete and moreover in many cases unreliable," R-Sport agency quoted Stanislav Pozdnyakov, the deputy chief of Russia's Olympic Committee, as saying.
"For the moment none of Russia's 1,000 athletes mentioned in the McLaren report has been found guilty or banned on the basis of his information.
Meanwhile, a year has already passed (since the report was issued)."
While this latest twist may help bolster the Kremlin's claims, Niggli suggested to the New York Times that an absence of evidence did not necessarily prove Russia's innocence.
"The system was very well-organised," Niggli said. "On top if it, years after the fact, the remaining evidence is often very limited."
Niggli said that investigations into other athletes implicated in the doping scheme are ongoing.
Russia's anti-doping agency Rusada is currently battling to get itself reinstated, but faces a list of remaining Wada criteria that it must first meet.