Vanzara had claimed, they said, in the resignation letter that he and other accused officials had implemented the "conscious policy of this government, which was inspiring, guiding and monitoring our actions from very close quarters".
According to the sources, he also said during questioning that Shah, who was Minister of State for Home, "ditched" the police officers who got embroiled in the encounter cases.
Vanzara, who is lodged in Sabarmati jail after CBI named him as main accused in the 2004 fake encounter case, was quizzed about the contents of his resignation letter in which he also faulted Modi.