CBI sources said the inquiry was initiated last week on the basis of a source information.
The sources said that the agency might soon call the officer to examine in this regard.
They said Pradip Chhabra, Deputy Director, had allegedly submitted fabricated documents to justify the expenditure incurred.
Chhabra did not send his reaction despite acknowledging the receipt of the emails seeking his comments in this regard.
"We are looking into the matter. We are looking to ascertain whether their was a bribery angle involved in the matter. But this is just a preliminary enquiry and anything concrete can only be said after some prima facie material is found against the suspect officer," a CBI official said.