In an 874-page written brief summarizing his defense, Karadzic said he should not be convicted by the U.N.'s Yugoslav war crimes tribunal, but acknowledged that, as wartime leader of the breakaway Serb entity in Bosnia, he "bears moral responsibility for any crimes committed by citizens and forces of Republika Srpska." In his written arguments, Karadzic said he was unaware at the time of the slaughter of Muslim men and boys by Bosnian Serb forces at Srebrenica in 1995 — the worst massacre in Europe since World War II — and said evidence at his trial called into question the number of people killed — widely accepted as more than 7,000 — and whether the slayings amounted to genocide.