Husain Haqqani, a Boston University professor on leave, last week stepped down amid accusations that he engineered the memo, a charge he denies.
The scandal exposed the depth of civil-military mistrust in Pakistan, where the military retains firm control of foreign and security policy three years after officially ceding power to Zardari’s civilian government.
The memo - which was given to Admiral Mike Mullen, then chairman of the Joint Chiefs of Staff, after the US raid that killed Osama bin Laden in May - sought assistance fending off an army coup in exchange for US-friendly policies.
Even so, the memo’s existence has roiled Pakistani politics. The court-ordered investigation could imperil the government if it reveals that Zardari or other high-level government officials knew about the memo.
In a statement, Haqqani said he had no intention of leaving the country.
“I resigned to pave the way for a transparent investigation and intend to stay in my country for as long as necessary,’’ he said.
Asma Jahangir, the country’s most prominent human rights lawyer, said yesterday that she would represent Haqqani.
The controversy is a “swirl of media allegations initiated by a reckless individual,’’ Haqqani said. He was referring to Mansoor Ijaz, a Pakistani-American businessman who first brought the memo to light in an October column he wrote for the Financial Times. Ijaz said he crafted and passed along the memo on the instructions of Haqqani.
Material from the Associated Press was used in this report.