Lax security allowed an assassin to approach within feet of Benazir Bhutto but the populist politician's decision to open a hatch in her bombproof vehicle and chat with jubilant supporters ultimately caused her demise.

Bhutto, who died Thursday in a gun and suicide bomb attack, reveled in personal campaigning and directly engaging her supporters, traits that fueled her popularity among many of Pakistan's desperate poor, but also posed a challenge for the security forces assigned to protect her.

"She was a very brave lady and sometimes when you see the supporters and cheering crowds there is a tendency not to heed the security department, and that's exactly what happened, unfortunately," Interior Ministry spokesman Javed Iqbal Cheema said Sunday.

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Even before Bhutto returned to Pakistan in October from eight years in exile, she was warned suicide squads were targeting her. At her homecoming parade in Karachi, twin bombers struck her convoy, killing about 150 people, some of them the police assigned to protect her.

She complained bitterly in recent months that her life remained in danger and that the government of President Pervez Musharraf, was not giving her the proper protection.

In an October e-mail that an associate forwarded to CNN's Wolf Blitzer and U.S. Rep. Steve Israel, she said specific security improvements she had requested were ignored. "I have been made to feel insecure by his (Musharraf's) minions," she said.

Bhutto, who was leading her party into parliamentary elections, had blamed elements in the ruling party for the threats against her. The government said Al Qaeda-linked militants orchestrated her killing Thursday, a claim both the militants and Bhutto's aides rejected.

The security around Bhutto was inconsistent. A reporter was able to walk into a recent rally in Nawab Shah in her southern Sindh province last week without being frisked or passing through a metal detector. Her supporters pressed up against the stage, just feet from where she was speaking.

"The government has never provided appropriate security to Benazir Bhutto," said Aghasiraj Durrani, a senior official in Bhutto's party. Many Bhutto aides questioned how the government was able to protect the president and other targeted government officials, but not the popular opposition leader.

Bhutto herself took risks. She declined to wear a bulletproof vest, and during her 10-hour, slow moving procession through the streets of Karachi on Oct. 18, she refused to use a bulletproof glass cubicle that had been built atop her truck, standing instead along a railing to greet the massive crowds.

Cheema said security officials repeatedly expressed concerns to her staff that she was exposing herself too much, but prominent opposition lawyer Athar Minallah said it was the government's job to protect her in all circumstances.

"She was a political leader. Meeting the people was something she could not avoid," he said.

At the Rawalpindi rally where Bhutto was slain, hundreds of police in riot gear ringed the park where she spoke, frisking those entering and making most pass through metal detectors. Police snipers could be seen in at least four positions on nearby rooftops. A 10-meter security zone was cordoned off in front off the stage, which was flanked by guards in plainclothes carrying assault rifles, presumably party members who bolstered her official security detail.

The stage had been swept by security officials and inspected by bomb-sniffing dogs, Rawalpindi police chief Saud Aziz said.

"There were ample security arrangements there," he said.

The attack occurred several minutes after the rally ended, when Bhutto's vehicle drove out of the park onto the road outside. Cheema said her vehicle was protected by four police mobile units comprising a total of 25 or 26 officers.

A video of the attack shows Bhutto poking her head out of the sun roof of her heavily armored SUV and speaking with a crowd of supporters swarming the vehicle. A man approaches, fires three shots and then a bomb explodes.

"Why was the road not blocked and cleared of people when Benazir Bhutto was coming out, and why was the security so lax in and outside the ground?" Durrani asked.

Talat Masood, a former army general and security analyst, said specially trained officers should have been scanning the crowd for potential attackers and Bhutto's guards should have created a security perimeter around the former prime minister's vehicle wide enough to protect her from a shooting or bomb attack.

"There always has to be a radius around her, and you can't leave her unprotected for even a second," he said. "The security undoubtedly was below the mark, much below the standards required for a leader of her stature."

Aziz said police were trying to secure her vehicle, pointing out that one officer was among the roughly 20 people killed in the blast and six others were seriously injured.

Bhutto was one of many major figures in Pakistan under threat.

Musharraf himself survived two assassination attempts in 2003. In its aftermath, security was tightened for top officials, and roads are sealed off when Musharraf or the prime minister are on the move.

But security protection for others is spotty.

Just days before Bhutto's killing, former Interior Minister Aftab Khan Sherpao narrowly survived a suicide bombing in a mosque at his compound that killed 56 worshippers — the second such attack against him in eight months. Police said everyone who entered the compound passed through a metal and explosives detector, and Interior Minister Hamid Nawaz insisted there was no security lapse.

On a campaign trip to Kashmir last month, former Prime Minister Nawaz Sharif — whom the government said was also under threat — was trailed by a single police van as he rode in an apparently unarmored sports utility vehicle. At one point, he stuck his head out of the sunroof and greeted hundreds of party supporters, much like Bhutto was to do weeks later.