(CNN) -- A year ago Sunday, Neda Agha-Soltan died of a single gunshot wound to the chest. Her last moments -- captured on a cell phone camera and shown around the world-- catapulted her into the symbol of the postelection reform movement in Iran.

Today, the Iranian regime's crackdown seems to have driven protesters off the streets. But the movement is not weakening, some analysts say. Instead, it's evolved into an online underground civil rights struggle, they say.

"I think they're going to continue to move forward, whether in the form of a green movement or another type of movement," said Karim Sadjadpour, a fellow at the Carnegie Endowment for International Peace. "It's just, basically, this march of history."

Agha-Soltan, 26, was at an anti-government demonstration in Tehran when she was felled by a single bullet to the chest.

"She has been shot! Someone, come and take her!" shouts one man in the shaky cell phone video that has since been seen around the world.

The video then shows blood streaming from her mouth, then from her nose. Her eyes roll to her right; her body is limp.

A man, who had accompanied her to the rally, is then heard pleading with her by name.

"Neda, do not be afraid, do not be afraid," he repeats.

Agha-Soltan was taken to a nearby hospital and, within a day, she was buried at Behesht Zahra, the city's largest Muslim cemetery, on the outskirts of the capital.

Immediately afterward, she emerged as the face of the anti-government movement.

Even world leaders took notice.

"We've seen courageous women stand up to the brutality and threats and we've experienced the searing image of a woman bleeding to death on the streets," said President Barack Obama.

Eight days before Agha-Soltan's death, Iranian President Mahmoud Ahmadinejad's landslide election victory unleashed massive demonstrations in the country.

Thousands of green-clad protesters took to the streets, accusing the government of rigging the elections.

Iran's leaders called the uprising a foreign-led plot to overthrow the regime. It cracked down on the protesters -- with many killed and even more jailed.

Images of the bloody crackdown fueled worldwide outrage. Agha-Soltan's pictures are still carried on placards at rallies outside Iran.

"She will become the image of this brutality, and of the role -- the truly significant role -- that women have played in fighting this regime," said Abbas Milani of Stanford University in California. "I think that women are the unsung heroes of the last few years. They are the ones who began chipping away at the authority, the absolute dictatorship of the mullahs."

Iranian authorities continue to deny that security forces were responsible for killing Agha-Soltan.

Instead, they have offered at least three separate explanations. They have blamed the CIA, terrorists and supporters of the opposition movement themselves.

One year after Agha-Soltan's death, Iranian officials have yet to announce a single arrest in connection with her killing.