Code "Red" declared in bulgarian post offices after someone sent a suspicious letter to the ambassador of Israel

Bulgarian post offices declared code "Red" after someone sent suspicious package to the ambassador of Israel and after the wave of letter-bombs in neighbouring Greece. This is the highest alert code. After several hours news agencies reported that the police did not find a bomb in the suspicious package. No more information about this case is available right now - what was in the letter if not bomb and from where it was sent - Greece or Bulgaria. Police announced that for the last four months they have found 41 weapons hidden in post packages including one army grenade.