Security agents chased down and pummeled the pro-democracy protester, who said his pursuers were celebrating as if they were “fishermen who just made a catch.”
“‘Who are you?’” the protester, Ahmed Sanhouri, recalled the agents demanding. He carried no identification or cellphone, and he insisted he was a laborer.
He is, in fact, a young doctor, but that is something that has been dangerous to admit in Sudan in recent months. Doctors have played a central role, along with other professionals, in organizing the mass protests that recently toppled the longtime autocrat Omar Hassan al-Bashir and fostered a powerful, if still uncertain, pro-democracy movement.
“Doctors had a great role, and they still have a great role, in this revolution,” said Dr. Mohamed Nagy Al-Asam, 28, a leader of the movement.
In Sudan, where the government and its allied militias had committed atrocities across the country’s south and west over decades, it was not an armed group or a long-running opposition party that forced out Mr. al-Bashir. That accomplishment belongs in large part to a semi-secret alliance of doctors, lawyers, journalists, engineers and teachers organized under the bland name, the Sudanese Professionals Association.
Doctors have played a particularly striking role in shaping the protest movement. Its most identifiable leader for many Sudanese is Dr. Al-Asam, and one of its most famous victims was a doctor killed while trying to treat wounded protesters.
Behind the scenes, doctors helped transform what started as protests over bread prices into a coherent movement, complete with a declaration of demands and a tightly organized protest schedule that survived months of repression. Their prominence reflects the fact that this revolution has been guided by the disintegrating middle class around the capital, Khartoum — a demographic easy to overlook amid Sudan’s woes.
Before toppling a dictator, the Sudanese Professionals Association was best known for a minimum wage study it undertook last year.
Now it falls to the association and the relatively narrow demographic it represents to unite disparate opposition factions — from left-wing groups to religious parties to armed rebels — around a political agenda that calls for civilian rule, women’s empowerment and an end to the nation’s civil wars.
The first of those goals, civilian rule, is the most immediate. The protesters may have forced out Mr. al-Bashir, but they still have to contend with the junta of generals that quickly declared itself in charge, at least for the time being.
The doctors’ activism and the government’s antagonism have deep historical roots.
Mr. al-Bashir’s regime regarded doctors with suspicion going back to 1989, when an Islamist-backed coup delivered him to power. Some of the earliest organized resistance came from doctors, who organized a strike. The government rounded up those involved: One died in custody from a blow to the head, and another was sentenced to death before an international outcry led to his release.
“Ever since then, the government, of course, had this opinion that doctors are against the government,” the man sentenced to die, Dr. Mamoun Hussein, said in a phone interview. “So their treatment of doctors was according to this concept,” said Mr. Hussein, now 84.
Amid the cronyism and repression of Mr. al-Bashir’s government, many Sudanese doctors left the country. According to one estimate, more work abroad than in Sudan.
Some doctors who stayed behind aligned with the regime, growing wealthy and leapfrogging over colleagues for top jobs. But deteriorating conditions also fostered discontent and led many others to speak out.
One gastroenterologist, Nada Abdalla, 48, spent more than a decade as a doctor in England before returning to Sudan a number of years ago.
Supplies became so scarce, she said, that doctors grew accustomed to dispatching patients’ relatives to pharmacies to buy gloves, sutures and gauze. Dr. Abdalla recalled a recent encounter in which a father tried to figure out how to afford medicine for his ill sons, 6 and 8, who were sharing a hospital bed.
She heard the father tell a doctor: “‘Tell me which one is sicker and which medicine is most important and I will pay for it.’”
It is scenes such as this that have encouraged doctors over the years to organize underground unions and to go on strike, putting them in a place to lead the current movement. Other professional groups were doing the same, and they came together in the Sudanese Professionals Association.
During the current protests, doctors set up clinics and treated gunshot wounds, the effects of tear gas and other injuries.
When protesters were killed, doctors tried to ensure the fatal wounds were documented before the government could cover up the cause of death. They took pictures of wounded protesters, copied medical records and sent the material to protest organizers to expose the brutality.
Dr. Mohanad Mohammed Hamid, a 28-year-old physician who oversaw teams of doctors treating wounded protesters, said that the government often forced doctors or family members to sign false documentation. One protester, he recalled, was initially recorded as having drowned in the Nile.
“There was no water in his lungs,” Dr. Hamid said. Instead, he said, the body showed signs of torture.
But all this also made doctors and medical centers the targets of government security forces, who have stormed clinics and filled hospital wards with tear gas, according to a report by Physicians for Human Rights.
In January, security forces shot and killed a 27-year-old doctor, Babiker Salama, who had wanted to treat a badly injured protester. Dr. Salama, who came from an affluent family of professionals, became a symbol of the movement and galvanized its protesters.
Doctors have also been jailed for months and questioned about their colleagues.
“Of course, I knew that I would be arrested.” said Dr. Al-Asam, who agreed to become the face the movement in a Facebook video released in early January. Three days later, paramilitary forces tracked him down and brought him to Khartoum’s main prison, Kober.
The protests ebbed and flowed before a breakthrough on April 6, when the Sudanese Professionals Association called for a march on the army’s headquarters. That day, instead of dispersing the protesters, the soldiers allowed them to stage a huge sit-in outside the gates.
Dr. Al-Asam could hear the chanting from Kober.
Five days later, Mr. al-Bashir was deposed in a coup by military officers who appeared to be acting in response to the demonstrations. Dr. Al-Asam was told he was free to go. He hurried home, changed his clothes and got a haircut.
Then he returned to the crowd of protesters still gathered outside army headquarters.