Three accused in the September 29 Malegaon blast on Saturday underwent polygraph tests at the Kalina Forensic Science Laboratory.
Pragya Singh Thakur, a sadhvi, former Army official Ramesh Upadhyay and Sameer Kulkarni were brought to the laboratory and tests are being conducted, police sources said.
"Some of these accused had the tests performed on them on Friday as well," they said, adding that narco-analysis was still to be performed on them.
Five persons, including the sadhvi, have been arrested for planting a motorcycle bomb in Malegaon which claimed six lives.
A magistrate's court in Nasik had granted permission to the ATS for conducting polygraph and narco-analysis tests on the three accused.
A serving officer with the army and two other former army officials working at the Bhonsala Military School in Nasik have been brought to the city by the Anti-Terrorism Squad for questioning.
Shailesh Raikar and Rajan Gaidhani, both employees at the school, were brought to the city on Saturday where they will be questioned.
Investigators suspect that conspiracy meetings prior to the blast may have been held at the school, a claim denied by the school's administration.