CBI sources said several questions about the crime, his conversations with his wife Indrani Mukerjea and his own statements were put to him during the test by CBI officials at the Central Forensic Science Laboratory.
They said there were some questions where there were indications of "deception".
The agency has received the nod from a special court here to subject Peter to polygraph tests.
The agency will have to produce Peter before a special court in Mumbai on Monday which has given it his custody.
The sources claimed that on many accounts his answers were purportedly not convincing and changing which prompted CBI to put him to polygraph test.