Ali Juraisha was a prominent, major Ikhwani figurehead and he stated in his book (الاتجاهات الفكرية المعاصرة), "Contemporary Ideological Orientations" (p. 279):

A group split (away) from a large Islamic group during their presence in the prisons ... and alongside that, that group sought recourse to making Takfir of that large group; because (this small group) did not cease being upon its own viewpoint regarding Takfir of the ruler, and the aiders of the ruler, and then the whole society. Then the aforementioned group [itself] split into many factions, each of them making Takfir of the other.

He is speaking here of the mid 1960s in which the Takfiri-Leninist methodology came out from the prisons of Egypt and took its course through the society.