Purohit had been listed as a witness by the CBI in the case related to the blast at the Mecca Masjid in Hyderabad on May 18, 2007 which killed nine persons and injured several others.
The case was later taken over by the National Investigation Agency (NIA).
A sessions court which is conducting the trial in the case had summoned Purohit as a prosecution witness on Wednesday, a prosecution officer said.
During his deposition, Purohit said he had worked as an intelligence officer in the Army, and whomsoever (among the accused) he had met, it was only while discharging his official duty.
He denied that he was examined by the CBI in the Mecca Masjid blast case. The CBI never recorded his statement when he was lodged in the Nashik jail, he claimed in the court.
Contradicting the CBI's contention, Purohit said he didnt know Bharat Bhai, one of the accused. He knew Swami Aseemanand, another accused, Purohit said, but the two never spoke about the death of Sunil Joshi, a co-accused, he stated.
The prosecution declared him as hostile after he denied giving any statement to the CBI.
The Supreme Court granted bail to Purohit in the 2008 Malegaon blast case in August 2017, after he spent nine years in jail.
The Hyderabad court has examined 222 witnesses in the Mecca Masjid case so far. The next hearing would be on February 26.
Two of the eight accused in the case -- Swami Aseemanand and Bharat Mohanlal Rateshwar alias Bharat Bhai -- are on bail, while three others are in jail.
Two accused are absconding, while Sunil Joshi, another accused, died.