A judicial investigation has concluded that the country's former ambassador to the US did write a letter to American officials seeking their help in reining in country’s powerful military, Pakistani state TV and an opposition leader said.
The investigation result could lead to treason charges against Husain Haqqani, and possibly add to pressures on President Asif Ali Zardari.
Zardari himself could be threatened if any evidence surfaces showing he ordered, or knew of, the memo.
Haqqani has denied any role in the affair and said the commission report was "political and one-sided".
Imtiaz Tyab | Correspondent
The accusations were brought to light by Manzoor Ijaz, an American businessman of Pakistani decent.
Ijaz claimed to have delivered the memo to US Joint Chiefs of Staff Admiral Mike Mullen on Haqqani’s behalf.
If true, Pakistani legal experts have said Haqqani could be charged with treason.
The Pakistani media has breathlessly covered every angle of this story since it began unfolding last year and has been searching for any links the scandal may have to the president’s office.
The former envoy, who resigned from his post after the scandal broke, said that his lawyers would be challenging the commission’s proceedings.
The commission was investigating politically explosive allegations that Haqqani sought US assistance last year in warding off an alleged military coup in the aftermath of the US raid that killed Osama bin Laden.
The scandal pitted the weak civilian government against the army, and drew in other the feuding power brokers in Pakistan - the Supreme Court, the opposition and the media.
The accusations were brought to light by Manzoor Ijaz, an American businessman of Pakistani decent with a history of making unsubstantiated allegations.
The report was read out in court and is due to be released later on Tuesday.
Opposition legislator Khwaja Asif said the investigation concluded Haqqani tried to undermine Pakistan's constitution and was not "loyal to the state”.
Retired Justice Nasira Javed said the commission was working on orders from the Supreme Court and said that criminal proceedings against Haqqani on treason charges could now begin.
Supporters of Haqqani and the government accuse the Supreme Court and the army of working against Zardari and the political party he heads.
Allegations of collusion between Washington and Pakistani officials may also complicate American efforts to rebuild security co-operation with Pakistan, thrown into disarray in November by accidental US airstrikes that killed 24 Pakistani soldiers along the Afghan border.