a hawk in the henhouse

Translations
ястреб в курятнике
Having the corrupt official in charge of the anti-corruption department is like having a hawk in the henhouse.
Иметь коррумпированного чиновника во главе антикоррупционного отдела — все равно что ястреба в курятнике.
Definitions
A person or thing that poses a threat or danger in a vulnerable or unprotected environment; someone with harmful intentions placed among those who are defenseless or unsuspecting.
Words
a

article or possessive pronoun
некий
hawk

noun
ястреб
in

preposition
в
the

article or possessive pronoun
этот
henhouse

noun
курятник