Israeli Prime Minister Shimon Peres promised to protect the beleaguered head of Shin Bet, Israel's secret service, after official warnings that the anonymous official -- known as "C." -- and five other security chiefs would be held responsible for lapses before the assassination of Yitzhak Rabin. A commission on the murder has increasingly focused on performance lapses by Shin Bet. Israeli radio reported that C. is being held responsible, above all, for Shin Bet's failure to warn police about plots to kill Rabin. Monday morning, in a sign that traditonally portends firings, the commission delivered private letters to the security officials and the head of the precinct where Rabin was killed November 4. But hours later, Peres said he would take no action against the Shin Bet chief until the commission completes its investigation: "Whatever it finds, I will respect."