CBI sources said the sharpshooter, Afroz alias Chunnu Pehlwan, was arrested on June 8 but it was not disclosed as his interrogation was going on for five days after taking permission from a local court.
The arrest was not made public as it was a sensitive matter, they said.
Afroz has been sent to judicial custody by the court after CBI informed that it has completed his examination and there was no need for his further police custody.
The then MLA from Mohammadabad in Ghazipur district of Eastern Uttar Pradesh, Rai and six of his supporters were shot dead on November 29, 2005 by a group of assailants armed with AK 47 rifles while the leader was returning after inaugurating a cricket match in the region.
Rai's body was riddled with over 21 bullets. The Allahabad High Court had ordered a CBI inquiry into case after his wife Alka Rai raised the demand.
