Terms for subject Proverb containing that's what it is

English	Russian
that's what lies at the bottom of it all	вот тут-то и собака зарыта
that's what lies at the bottom of it all	вот где собака зарыта
that's what's behind it all	вот тут-то и собака зарыта
that's what's behind it all	вот где собака зарыта