Callen's father assumed the name Konstantin Chernoff.
Hetty came to Callen with information she found in the Kremlin's system after Callen had asked Eric to dig into it for him.
There was man whom Arkady dealt with in Russia until 1988 named Konstantin Chernoff. There are no records of that man before 1974, the year Nikita Reznikov was sent to the Gulag. Hetty and Callen deduced that Callen’s father escaped, then dropped the name Reznikov and assumed the name Chernoff. Chernoff lived in Ruza, about an hour west of Moscow.