The narrator tells the story in the third person, but with the words, tone, and way of thinking of a character, without quotation marks or "he thought": the voice of the narrator and that of the character blend.
In The Master and Margarita
There was no shadow of doubt that the mysterious consultant had known in advance of the whole scene of Berlioz's terrible death.
"There was no shadow of doubt" is Ivan's own certainty, spoken in the narrator's voice, without quotation marks or "he thought." The blend gives the poet's conclusion the firmness of a fact, though it is only his reasoning.
Part One, Chapter 4: The chase, The narrator (from Ivan's point of view)