JUBA, Sudan (AP) – Southern Sudanese gathered by the thousands Friday at the Episcopal cathedral in this southern city where their leader John Garang is to be buried in a granite-and-mud-brick tomb.

A hundreds-strong choir rehearsed for the ceremony and townswomen cooked red beans, okra and sorghum porridge to feed the multitudes expected at the state funeral on Saturday.

Garang’s body was taken by plane from town to town Thursday and Friday, allowing people to pay last respects to the man who died July 30 in helicopter crash just three weeks after he joined a unity government. Garang fought for two decades to ensure their equality within Sudan.

In the town of Yei, Ugandan President Museveni, Garang’s longtime friend and backer, told mourners that the cause of the crash was “not clear” and the focus of an international probe.

“Some people say accident, it may be an accident, it may be something else,” Museveni said, according to the British Broadcasting Corp. “The (helicopter) was very well equipped, this was my (helicopter) the one I am flying all the time, I am not ruling anything out.”

The Sudanese government and Garang’s rebel movement say the helicopter crash was an accident. The United Nations, Kenya and Uganda – who provided the helicopter – were participating in the investigation.

Garang’s body was to be received this morning in Juba by President Omar al-Bashir. Other dignitaries expected to attend the funeral included Museveni, South African President Thabo Mbeki and Kenyan leader Mwai Kibaki. The U.S. delegation will be led by Andrew S. Natsios, head of the United States Agency for International Development.

Hundreds of troops from both the national army and Garang’s Sudan People’s Liberation Movement have filled Juba in the last two days. On Friday, cargo planes dropped off more than 300 elite presidential guards, distinct in their maroon berets.

The soldiers carried weapons and cooking pots as they piled into trucks headed to their camps.

Others stayed behind to guard roads leading to the airport. Government troops also were out in force, with one soldier every 10 yards along key roads.

At the airport, hundreds of Juba’s Arab residents were being evacuated in cargo planes. Men, women and children ran in single file across the tarmac to the planes, carrying suitcases and prayer rugs tucked under their arms.

The town’s Arabs have been targeted in two days of rioting by southerners who blamed the government for Garang’s death. At least 130 people have died in violence across the country, according to the Sudanese Red Crescent.

Garang died shortly after taking office as first vice president in a unity government established under a peace deal ending 22 years of war between the Arab Muslim-dominated government and rebels in the African Christian and animist south. He also was installed as the president of southern Sudan’s autonomous government.

Garang’s widow, Rebecca, told mourners at a stop in Rumbek that they should keep their faith and continue on the road to peace.

“Garang is dead, but his vision for southern Sudan is alive,” she said, according to Sudan radio.

She urged all Sudanese to stop the violence and called on southern leaders to support the implementation of the peace agreement.

SPLM Gen. Aieng Deng said Friday that searchers have found the helicopter’s “black box” data recorder, but it has not been evaluated. It will remain at the site until investigators arrive Monday.

Responding to Museveni’s comments that the cause of the crash wasn’t clear, SPLM spokesman Yasir Arman said his group “asked for the investigaton to put the record straight and to establish what exactly has taken place.”

Yasir told The Associated Press that “it is the results of the investigation which are going to speak for themselves. … Until the investigation results are out, we are not going to point any fingers in any direction.”

At Juba’s All Saints Cathedral, a choir of hundreds rehearsed a mournful song in English about the peace negotiations between Garang and Vice President Ali Osman Mohamed Taha.

“He cried to him, ‘Oh my people, oh my people, who will set you free?”‘ they sang of Garang.

Mourners from surrounding villages already were gathering Friday, filling the grounds of the cathedral where Saturday’s proceedings will begin with a multidenominational service.

Carpenters and welders were working around the clock trying to finish Garang’s tomb, a one-story structure with a star-shaped chamber over the grave representing the “guiding star” in the SPLM flag. Garang’s son, Chol, watched.

“It is still a shock. It seems like a bad dream and that when I wake up I will see him. But all I find are people weeping,” he said.

“This was his life’s work for 22 years, so to actually be sworn in and then to die … ” he said, his voice breaking with emotion. “He died a free man. He died in his own country.”

Garang’s death and the clashes that followed raised fears about the stability of the peace deal struck in January. His charismatic – and sometimes strong-handed – leadership had been seen as essential to making the agreement work.

The accord provided for sharing of power and wealth with southerners. In six years, southerners are to have a chance to vote on secession.

Garang had argued for greater autonomy for the south, not independence, though other southern leaders wanted more. Without Garang, northerners who reject independence for the south may find it difficult to persuade southerners to stay.