expression, noun
birds of a feather; villains of the same stripe
Idiomatic expression used to say that people who do bad things together are alike or equally guilty. Often carries a negative connotation. Literally 'raccoon dogs of the same hole'.
See also: 同じ穴のムジナ
あの二人は同じ穴の狸だ。
Those two are birds of a feather.
詐欺師とその弁護士は同じ穴の狸だった。
The scammer and his lawyer were villains of the same stripe.
Synonymous expression using ムジナ (badger) instead of 狸. Essentially interchangeable, but 同じ穴の狸 is more common.
From the idea that raccoon dogs (狸) sharing the same den are alike in nature, extended metaphorically to people who collude in wrongdoing.