Zimbabwe's Prime Minister Morgan Tsvangirai has returned to Harare after receiving treatment in Botswana for injuries sustained in a car crash that killed his wife. 

Zimbabweans living in South Africa are voicing grief and suspicion over the incident.

Hundreds of Zimbabweans Sunday attended a memorial service for Zimbabwean Prime Minister Morgan Tsvangirai's wife, Susan, who died in a car accident Friday that also injured her husband.

The service was held at the Central Methodist Church in Johannesburg, which is home to several thousand Zimbabwean refugees.

Frank Danhira, who helps register new arrivals at the church, says Susan Tsvangirai was a mother to Zimbabweans and a pillar of the Movement for Democratic Change party. He blames her death on government officials.

"Those who are in the government, the MDC especially, they were reluctant. They were supposed to see that there was enough protection and enough escort for our prime minister. You see, now they are regretting but it's too late now," he said.

The accident occurred Friday evening south of Harare when a truck collided with Mr. Tsvangirai's vehicle causing it to roll several times. The prime minister's car was accompanied by two party vehicles.

Refugee Nyaradzo Shonhiwa says there should have been a police escort.

"From the word 'start,' there is a very, very big blunder which has been made," Shonhiwa said. "How can a prime minister with executive powers, who has a cabinet, his motorcade is just two or three cars?"

Zimbabwean authorities are investigating the incident. The MDC is carrying out its own inquiry.

Mr. Tsvangirai told supporters Monday after returning to Harare that the crash was an accident. But Evans Kuntonda, like many Zimbabweans, has his suspicions saying Zimbabwe has a long history of political violence.

"Those private investigators who are investigating the case right now, they should come up with whatever they come up with. Most of us here, we feel that it was an assassination but we need to hear what will come from the investigation," Kuntonda said.

Mr. Tsvangirai, a long-time opposition leader, became prime minister last month as part of a power sharing agreement with the ZANU-PF party of President Robert Mugabe.

Fortune Gora, who sells fruit on the streets of Johannesburg, believes the accident was planned by elements of ZANU-PF who oppose the power sharing accord.

"If I were a policeman I was going to [would] arrest Mugabe. Maybe he was going to [would] explain later or the courts were going to prove him guilty or innocent. Accidents have been one way of eliminating opponents. I think he is the one who planned this," Gora said.

Sibongile Chipunza, a young mother with a three-month-old baby, says she prays God will protect Mr. Tsvangirai.

"Without Tsvangirai there is nothing much we can do because Mugabe is a very, very hate[ful] man. He doesn't even care about us. Right now we are living in a foreign country. We are suffering, no food, no water. But God chose Tsvangirai to stand for us," she said.

The MDC is to hold a rally Tuesday in memory of the late Susan Tsvangirai. The 50-year-old mother of six is to be buried on Wednesday.