He was later arrested for his association with the left opposition, and served as an NKVD informant in prison, and gave fabricated evidence against over a hundred of his former comrades, in spite of which, he was executed on 27 July 1942.

Following the Bolshevik seizure of power and the outbreak of the Russian Civil War, Safarov backed the Left Communists who opposed the Treaty of Brest-Litovsk, wanting to conduct a 'revolutionary war'; against Germany,[5] and backed the Military Opposition, who opposed the recruitment to the Red Army of former officers of the Imperial Army.

On 29 June 1918, Safarov, as a member of the Presidium of the Ural Regional Soviet under Alexander Beloborodov, was a party to the unanimous decision to execute the Romanovs imprisoned in Yekaterinburg, who included the deposed Emperor Nicholas II, his wife Empress Alexandra, and their five children Olga, Tatiana, Maria, Anastasia, and Alexei.

In November 1919, Safarov was sent to Turkestan to take part in the suppression of the White Movement and the Basmachi there and the establishment of Soviet power in the region, and was a member of the Turkburo of the Central Committee of the RCP (b) from 1920 until 1922.

This brought him into a conflict with the new head of the Turkestan bureau, Mikhail Tomsky, which became so serious that the Poltiburo sent two senior Bolsheviks Adolf Ioffe,[7] and Grigory Sokolnikov to investigate.

Safarov was a political ally of Grigory Zinoviev, who was Chairman of Comintern and head of the communist party in Petrograd (St Petersburg).

In November, he wrote a tirade against Zinoviev's rival, Leon Trotsky, entitled Trotskyism or Leninism?, which ran across seven issues of Leningradskaya Pravda.

[citation needed] On 16 January 1935, he was again sentenced to 2 years of exile in the so-called "Case of the Leningrad Counter-Revolutionary Zinoviev group of Safarov, Zalutsky, and others" and again deported to Achinsk.

[citation needed] Almost every other former member of the Zinoviev opposition group was executed during the Great Purge, but Safarov survived by co-operating with the NKVD and denouncing others, but was sentenced to death by a decree of a Special Collegium of the NKVD on 16 July 1942 following the German Invasion of the Soviet Union, ironically on the same day Safarov had signed the death warrant for the Romanovs 24 years prior.

Without citing specific facts that could be used as a basis for accusing the persons named in anti-Soviet activities, Safarov attributed to them the holding of such and each of them a negative political characteristic.

Subsequently, in 1938–1940, during his time in prison, Safarov was used as a witness and a provocateur on the instructions of state security personnel, and also, on his own initiative, gave testimony to numerous individuals.

[citation needed] Safarov reported in a statement dated 10 September 1941 to Vsevolod Merkulov, that for more than two years he has been "rigorously fulfilling the tasks of the investigative unit for combating enemies of the people".