(CNN) -- Two months before her death, former Pakistani Prime Minister Benazir Bhutto sent an e-mail to her U.S. adviser and longtime friend, saying that if she were killed, Pakistani President Pervez Musharraf would bear some of the blame.

Bhutto was assassinated after the campaign rally, seen here, Thursday. more photos »

She cited his government's denial of her request for additional security measures after the October suicide bombing that targeted her upon returning to Pakistan from exile.

"Nothing will, God willing happen," she wrote to Mark Siegel, her U.S. spokesman, lobbyist and friend.

"Just wanted u to know if it does in addition to the names in my letter to Musharaf of Oct 16nth, I wld hold Musharaf responsible. I have been made to feel insecure by his minions and there is no way what is happening in terms of stopping me from taking private cars or using tinted windows or giving jammers or four police mobiles to cover all sides cld happen without him."

Bhutto was seeking to become prime minister for a third time when she was assassinated; her death comes exactly two weeks before Pakistan's January 8 parliamentary elections. Watch Siegel describe her concern and the reaction of Pakistan's U.S. ambassador »

Article Correction An earlier version of this report incorrectly attributed a quote to Mark Siegel, Benazir Bhutto's U.S. spokesman. The quote: "She was moving almost in a sea of humanity. No system in the world can protect you against that," was from Ambassador Mahmud Ali Durrani.

Pakistan's ambassador to the U.S., Mahmud Ali Durrani, on Thursday insisted Musharraf's government provided the former prime minister with unprecedented security. He said that terrorists and extremists, who also have targeted Musharraf, were the only ones responsible for her death. Watch a report on security provided to Bhutto »

Bhutto wrote the e-mail on October 26, eight days after at least 130 people were killed and hundreds more wounded in Karachi by the suicide bombing that occurred as Bhutto's motorcade passed.

Siegel forwarded that e-mail to CNN's Wolf Blitzer, with instructions he not report on it unless Bhutto was killed.

Just before returning to Pakistan after eight years of self-imposed exile, Bhutto told CNN she was aware of threats against her and said that some had come from people who hold "high positions" in Pakistan's government. She said she had written a letter to Musharraf about her fears, apparently the same letter she refers to in her e-mail to Siegel.

In a speech, she listed four groups she believed posed the biggest threat to her and her cause -- the Taliban in Pakistan, the Taliban in Afghanistan, al Qaeda and a suicide team from Karachi that she did not describe.

After the October bombing, she accused elements in the government and security services of trying to kill her and asked Musharraf for "basic security," including vehicles with tinted windows and private guards in addition to police guards. Three United States senators repeated the request in a letter to Musharraf.

Bhutto was concerned by the lack of security she had upon her arrival in Karachi and called the October 18 bombing "very suspicious," Siegel said. He accused Pakistani authorities of not investigating the assassination attempt and of refusing Bhutto's request for Scotland Yard and the FBI to aid in the investigation.

Bhutto and her husband had asked for jammers to impede the detonation of bombs; special vehicles with tinted windows; and four police vehicles to surround her at all times, Siegel said.

"She basically asked for all that was required for someone of the standing of a former prime minister," Siegel told CNN's "The Situation Room." "All of that was denied to her. ... She got some police protection, but it was sporadic and erratic."

Bhutto was concerned the problem was worsening as the January elections neared, Siegel said.

At the time of the October suicide bombing, Bhutto was riding in a truck from Karachi's airport to the tomb of Mohammed Ali Jinnah, founder of Pakistan. She had moved from the roof to inside the bulletproof, armed vehicle just moments before the blast and was unharmed.

CNN's Dan Rivers, in Karachi to cover her return to Pakistan, remarked at the time that her security appeared to be loose, saying his crew was able to walk up to the side of her vehicle without being stopped by authorities.

Durrani, Pakistan's ambassador to the U.S., insisted security surrounding Bhutto then was more than adequate.

"There were, I think, a sea of security people," he said. "She was surrounded by police vehicles. And had it not been one of the police vehicles which took the blast in Karachi, unfortunately she would have died there.

"There was a bubble around her of security. The PPP [People's Party of Pakistan, Bhutto's party] insisted that they have their own private loyalists around. They were there too. And there were about 7,800 to 8,000 security people deployed just for that," Durrani said.

"That is more security than anybody deploys anywhere in the world."

"She was moving almost in a sea of humanity," Durrani said. "No system in the world can protect you against that."

Bhutto "is not a security person," he said. "She's a politician. I think the government of Pakistan provided her all the security that was necessary. You tell me -- the way she was hit, she would have been hit with tinted windows or without, or without the IED ... so it's just a blame game."

After the October attack, Bhutto said police offered to let her use a helicopter for the trip from the airport, but she told them she wanted to be near her people. She said she did not regret that decision.

"She believed in democracy, and she believed in speaking to the people," Siegel said. "It's not reckless to go out and touch the people. Don't blame the victim for the crime. The person that was supposed to be protecting Benazir Bhutto and the other candidates was the government of Pakistan with the government of Pervez Musharraf."

Blitzer noted that Bhutto was shot Thursday while standing out of her vehicle's sunroof -- seen by some as a a reckless action after the October incident.

Getty Images senior staff photographer John Moore, who was at the scene of her assassination, told CNN he was surprised at Bhutto's actions, considering the earlier suicide attempt. The rally was smaller than expected, he said, and the people he spoke with said they "were just afraid to come out, for the simple reason that they all remembered what happened in Karachi."

Siegel grew emotional as he told Blitzer that Bhutto was "the bravest person I ever knew. ... She knew that there were risks coming back, but those risks were important, she thought, for the fight for democracy." E-mail to a friend

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