The United Nations team that probed Benazir Bhutto's assassination had met former Pakistani president Pervez Musharraf during its investigations, the commission's head, Chilean Ambassador to the UN Heraldo Muñoz, says.
This meeting was subject to the condition of confidentiality, Online news agency quoted Munoz as telling a private TV channel in an exclusive interview.
Munoz also said that the commission was initially told that Pakistan's intelligence agencies and army were "off limits".
It was only after the commission's insistence that army and intelligence officials agreed to be interviewed.
In another revelation, Muñoz termed as "inexcusable and irresponsible" the disappearance of the bulletproof black Mercedes that was to be Bhutto's back-up vehicle after she left the Dec 27, 2007 political rally in Rawalpindi at which she was killed.
The UN commission's report detailing the probable causes of Bhutto's death contradicts President Asif Ali Zardari's claim that it had absolved the ruling Pakistan Peoples Party (PPP) of any blame.
Senior PPP party members Farhatullah Babar and Rehman Malik, who is now the interior minister, were sitting in the Mercedes, along with Babar Awan, now the law minister, and Gen. (retd) Tauqir Zia, the report says.
According to eyewitnesses, the Mercedes left Liaquat Bagh, the site of the rally, before Bhutto's vehicle and was nowhere to be seen afterwards.
The commission said it found it "incredible" that the occupants of the Mercedes drove all the way to Zardari House some 20 minutes away before they became aware that Bhutto had been injured in the attack on her.
The report has thrown the spotlight on government officials, intelligence agencies and the police as it highlighted various security lapses on Dec 27, 2007.
The report has directly blamed Musharraf's government for failing to provide Bhutto adequate security in Rawalpindi, where a suicide bomber shot at the PPP leader during the rally and then blew himself up.
The report terms the government's failure to protect Bhutto "inexcusable".
Musharraf's aide Rashid Qureshi has denied allegations that the former president was responsible for Bhutto's death, and on Friday said the UN report was based on rumours.
Qureshi said Bhutto exposed herself to the risks in Pakistan even though the Inter-Services Intelligence (ISI) warned her not to attend the Rawalpindi rally.
The report says the police performance on the day of the assassination was "poor" and that Islamabad's city police officer Saud Aziz "impeded" the investigations.
It says Aziz was not acting alone and suggests that he was taking orders from Major General Nadeem Ejaz Ahmed, who was the director of Military Intelligence.
Noting that the police was "subordinate" to the intelligence agencies in terms of collecting evidence and conducting investigations, the report says: "Given the historical and possibly continuing relationships between intelligence agencies and some radical Islamist groups, the agencies could be compromised in their investigations of crimes possibly carried out by such groups."
According to the report, the involvement of intelligence agencies in all spheres of Pakistani life had undermined the rule of law and weakened political and law enforcement institutions.
In the fall-out of the UN report, officials named in the document are being investigated and have been relieved of their duties.
Munoz's assertions that the intelligence agencies refused to cooperate and that the missing Mercedes was key to the case, however, highlight areas where action is not being taken, Online said.