When it comes to protecting Israel's national security, Mossad does not play nice. The Israeli spy agency, which has a long and bloody history of extrajudicial assassinations under its belt, is suspected of adding another in the slaying of a Hamas researcher on Dec. 15 in Tunisia. The death of Mohammed al Zoari in a hail of gunfire in the coastal city of Sfax came at the zenith of a complex operation involving as many as eight Tunisian nationals and an unknown number of others, who Tunisian officials said were foreign agents. Although the hit carried the hallmarks of other Mossad operations, Israel has hinted at, but not acknowledged, its involvement. “If someone was killed in Tunisia, he’s not likely to be a peace activist or a Nobel Prize candidate,” said Israeli Defense Minister Avigdor Liberman.