However, after Harhoff's letter leaked into the public earlier this year, Seselj demanded he be removed from the trial, saying Harhoff appeared biased toward convicting Serbian leaders.
In the letter, Harhoff wrote that it was "more or less set practice" at the tribunal to convict military commanders for crimes committed by their subordinates and lamented recent judgments that eroded the practice by acquitting senior commanders.
He also wrote that he had always "presumed that it was right to convict leaders for the crimes committed with their knowledge."
By a 2-1 majority, a panel of judges established to rule on Seselj's request said that the letter's contents mean "an unacceptable appearance of bias exists."
Harhoff did not immediately respond to the decision.
However, his position at the court now appears untenable. Even a Chinese judge who disagreed with the decision to remove Harhoff was scathing about the letter.
In a dissenting opinion, Judge Liu Daqun described the letter as, "an inarticulate critique of the recent jurisprudence of the Tribunal based on unsubstantiated speculations and insinuations of improper conduct by other colleagues in a fashion that is unbefitting of a Judge."