Former deputy South African Revenue Service (Sars) commissioner Ivan Pillay and the revenue service’s former head of strategy Johan van Loggerenberg will appear before the Directorate for Priority Crime Investigation (Hawks) on Thursday as part of the politically-charged probe into the so-called rogue spy unit which also targets Finance Minister Pravin Gordhan.

“They have agreed to appear and it is expected they will be asked to provide warning statements and that specific questions will be put to them,” a source close to Pillay and Van Loggerenberg said.

Gordhan, Pillay, Van Loggerenberg and two other former Sars employees were on Monday sent letters from the Hawks informing them that the investigation into the intelligence unit had been completed and that they should present themselves on Thursday to give their versions of events.

It is reliably understood that Gordhan will not do so. National Treasury has confirmed that the minister has received the letter and was seeking legal advice, but would not comment further.

The allegations that an illicit intelligence gathering unit was set up on his watch as Sars commissioner have returned to haunt Gordhan in an increasingly threatening manner since he was brought back to his old portfolio as finance minister late last year after the fiasco of Nhlanhla Nene’s replacement, briefly, with Des van Rooyen.

Gordhan insists the unit was established lawfully.