Johannesburg - Finance Minister Pravin Gordhan is not only facing possible arrest by the Hawks – the SA Revenue Service (Sars) has also launched a massive new forensic probe into deals concluded during his tenure at the organisation.Finance Minister Pravin Gordhan (File)News24 can reveal that Sars appointed accounting firm Grant Thornton to conduct a forensic investigation into its modernisation and technology programme, which was implemented between 2007 and 2014. Gordhan was Sars commissioner from 1999 until 2009.The Daily Maverick on Tuesday night reported that the Hawks had asked Gordhan, his former deputy at Sars Ivan Pillay, and three other senior former Sars officials to provide warning statements.A warning statement is a precursor to a suspect being charged criminally.Hawks summon former Gordhan colleaguesGordhan, Pillay, former head of risk Pete Richer and Johann van Loggerenberg, former head of the Sars investigations unit called the National Research Group, were summoned to appear before the Hawks on Thursday morning.The Western Cape Hawks had already obtained a warning statement from Van Loggerenberg’s predecessor, Andries “Skollie” Janse van Rensburg.READ MORE:- Sars wars: DA fears arrest of GordhanTreasury spokesperson Phumza Macanda said Gordhan had received correspondence from the Hawks and was considering his legal options. His lawyer Tebogo Malatji told News24 the minister “would decide tomorrow (Wednesday) if he would make any further statements”.A criminal attorney who did not want to be named told News24 a warning statement was taken when formal charges were put to a suspect.“This is accompanied by the taking of fingerprints and is a precursor to the suspect appearing in court,” he said.‘Project Sunday Evenings’News24 understands Gordhan and his four former colleagues were expected to be charged under the Regulation of Interception of Communications and Provision of Communication-Related Information Act of 2002, and the National Strategic Intelligence Act of 1994.The charges related to the alleged establishment of intelligence capacity in Sars; the recruitment of investigators to work for this unit, and “Project Sunday Evenings”. The latter was an allegedly illegal Sars operation to record conversations of members of the now-defunct Scorpions unit.READ MORE:- Gordhan seeking legal advice over HawksIt was not clear what the Hawks would allege Gordhan’s role or knowledge of these matters was.News24 has been told all five would be asked to respond to more than 30 questions and return their answers to the Hawks next month. Technically, the Hawks could then still reconsider charging them.Grant Thornton on Monday said its forensic investigation at Sars was in progress.The firm was “specifically appointed to conduct an independent preliminary forensic investigation of the Modernisation and Technology Programme from 2007 to 2014”. This was according to a statement in answer to News24's queries, issued by communications firm StratComms. The programme was started in 2007 and saw Sars adopt new software and IT systems, such as its e-filing platform and its electronic system for customs payments.It is understood that two transactions in particular had been in the Grant Thornton investigators' sights: one involving software development firm BBD and another involving state-owned software firm Interfront.The Grant Thornton probe was known within Sars as "Project Lion", say sources familiar with the development.'Find dirt' on GordhanThe sources claimed the latest investigation was an attempt by current Sars commissioner, Tom Moyane, to “find dirt” on Gordhan.READ MORE:- Moyane: Ask Hawks if Gordhan should be probedThey maintained the Grant Thornton probe should not be seen in isolation from the ongoing Hawks probe into the supposed “rogue unit”, which was allegedly established at Sars under Gordhan’s leadership.Moyane is the complainant in the Hawks’ case against Gordhan and his former colleagues.It is an open secret that Moyane, viewed as an ally of President Jacob Zuma, and Gordhan did not see eye to eye on issues affecting the troubled national revenue collector, especially since Gordhan reclaimed his former position as finance minister late last year.An earlier report on the “rogue unit” which Sars commissioned after Moyane became commissioner has since been criticized as a waste of taxpayer’s money. Auditing firm KPMG compiled it. The existence of a so-called rogue spying unit within Sars has since been cast in doubt. The Sunday Times, which ran a series of articles on the issue in 2014 and 2015, publicly apologised for its reportage.The scope of the Grant Thornton probe meant other former Sars officials who left the entity in the wake of the "rogue unit" saga, would again face scrutiny.FightbackGrant Thornton did not provide specific details on which companies or transactions it was investigating."Grant Thornton is bound by confidentiality agreements with Sars and the firm is therefore unable to disclose the terms and conditions of the appointment, including the scope of the investigation," the firm stated.It directed further questions to Sars.Sars spokesperson Sandile Memela did not respond to questions.Sources close to the developments said they should not be seen in isolation from the Cabinet announcement on Monday that Zuma would take charge of 40 priority investment projects and strategy of all state-owned companies, including SAA, Eskom, Transnet, and Denel.“The ANC has had a bad elections outcome under Zuma. Treasury is pushing back on SAA, Denel and Eskom. This is the fightback,” the sources said.