Official sources said BRTF Commandant Ram Milan, based in Arunachal Pradesh, had allegedly collected the amount as bribe from a private contractor in that state.
CBI received a tip off that Milan would be heading for New Delhi via Guwahati. Accordingly, a team of CBI officials kept a lookout at the Guwahati station and caught him while he was planning to board the Rajdhani Express.
On questioning by the CBI team, Milan was unable to reply about the origin of the cash found in his possession.
Further details regarding the incident are awaited.