The Hawks unit is investigating Public Protector Busisiwe Mkhwebane after a complaint was laid by anti-corruption pressure group Accountability Now.
Hawks spokesperson Hangwani Mulaudzi confirmed this to News24 on Wednesday.
Accountability Now laid criminal charges of perjury and defeating the ends of justice against Mkhwebane on Monday. It also lodged a maladministration complaint against her with the very office she heads.
The group sent a letter of complaint to the Office of the Public Protector on Monday and laid a criminal complaint with the police, which included a supporting affidavit from Accountability Now director Paul Hoffman, SC.
In a statement, the group said: "The criminal complaint has been given Ocean View CAS no 09/08/2019 and will be investigated by the Hawks in Pretoria.
"As she cannot investigate herself, the maladministration complaint will have to be investigated by her deputy."
Mkhwebane's deputy is Kevin Malunga.
Last month, Accountability Now asked the Legal Practice Council to strike Mkhwebane off the roll of advocates for perjury and for attempting to mislead the court.
This, after the Constitutional Court agreed with the Gauteng High Court in Pretoria that her entire ABSA/Bankorp investigation was flawed, and that Mkhwebane had not been honest during her investigation. The High Court set aside her Bankorp-CIEX report, which stated that ABSA had to repay R1.125bn, in February.
The National Assembly's Portfolio Committee on Justice will also investigate Mkhwebane's suitability for office, after the DA requested such a probe.
Several civil society organisations asked that this inquiry be expedited.