"The RFU are investigating a complaint made by Sale Sharks in relation to the passing of information to the opposition team ahead of the match against Bristol earlier this month," an RFU spokesman told British media.
The leaked information is reportedly about on-field tactics rather than playing squad.
"Bristol Rugby has been made aware of a complaint from Sale Sharks, which is now being investigated by the RFU," Bristol said in a statement.
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"The club are absolutely confident of no wrongdoing in this matter and will fully co-operate with the investigation."
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Amlan Chakraborty)
