"We have called for the CCTV footage of the polling booth and action will be taken after examining the same," Special Election Observer Praveen Kumar said.
Kumar also said that flashing of election symbol at the booth is violation of Section 130 of the Representation of Peoples Act and a report will be sent after inquiry into this matter to the Chief Election Commissioner.
A report has also been sought from the local administration into the matter.
Early Monday morning, Rai came along with his family members to cast his vote, while wearing a badge of Congress election symbol 'hand' on his kurta.
He, however, defended his action saying that he has the right to wear the symbol as a candidate.
Rai also claimed that the case against Narendra Modi cannot be compared with his action as the BJP Prime Ministerial candidate had shown his lotus symbol after casting vote in Gandhi Nagar.
Sensing stringent action, Rai later took a softer stance.
It was not intentional and was done unknowingly, he told reporters in Varanasi.
On April 30, BJP's Prime Ministerial candidate had courted trouble after he flashed his party's symbol lotus while taking a "selfie", and made a speech after casting his vote in Gandhinagar in Gujarat.
Modi is also fighting Lok Sabha elections from Varanasi.
Another candidate Arvind Kejriwal of AAP also raised objections about Rai wearing 'hand' badge on the polling booth and said this was not fair.
BJP leaders also raised objections and sought action against Rai by the Election Commission.
With Agency Inputs
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