In the 1930s, Stalin apparently became increasingly worried about the growing popularity of the Leningrad party head Sergei Kirov. At the 1934 Party Congress where the vote for the new Central Committee was held, Kirov received only three negative votes (the fewest of any candidate) while Stalin received at least over a hundred negative votes. After the assassination of Kirov, which may have been orchestrated by Stalin, Stalin invented a detailed scheme to implicate opposition leaders in the murder, including Trotsky, Lev Kamenev, and Grigory Zinoviev. From thereon, the investigations and trials expanded. Stalin passed a new law on "terrorist organizations and terrorist acts" that were to be investigated for no more than ten days, with no prosecution, defense attorneys or appeals, followed by a sentence to be executed "quickly."