The claims were made by Hari Nada in a letter dated April 19 to the independent directors on Nissan's board.
The investigation is in response to allegations of harassment against Gupta from a female employee, which were made in March.
Nissan declined to comment further on the investigation and did not make Uchida or other recipients of Nada's letter available for comment.
The investigation is being conducted by independent third parties.
Nissan remains divided over its relationship with Renault, its alliance partner, five years after the arrest of former CEO Carlos Ghosn.
Nissan and Renault have been in talks for months to finalize a new partnership deal.
In February, they announced a new agreement under which Nissan would take a stake of up to 15% in Ampere, an electric vehicle unit that Renault is spinning off, and Renault would reduce its 43% stake in Nissan.
However, the deal has been delayed and is now expected to be approved by the end of 2023.
Renault CEO Luca de Meo and Chairman Jean-Dominique Senard had criticized Rajesh Gupta, Nissan's chief performance officer, for slowing down or blocking the completion of the deal.
Nada, a member of Nissan's executive committee, wrote a letter in April criticizing CEO Hiroto Uchida for making concessions and commitments in backroom deals with Renault, and called for an independent financial adviser to review the Ampere deal.
Nada had previously cooperated with prosecutors in the case against former Nissan CEO Carlos Ghosn, who had been considering a full merger of the companies before his arrest in 2018.
Nada has also been involved in efforts to develop a rationale for Nissan's agreed investment in Ampere, but has not been able to provide a credible explanation.
Gupta's sudden removal from his position would serve as a warning to others perceived as being difficult or anti-Renault.
LONDON DAILY ARCHIVE
Nissan Launches Investigation into Allegations of Surveillance and Harassment Against CEO and Deputy
Nissan has launched an investigation into claims by a senior adviser that CEO Makoto Uchida carried out surveillance of his deputy Ashwani Gupta.
24 June 2023 · 20:29 UTC
