The killings mark a sharp escalation in political violence over the last few days as members of Robert Mugabe's Zanu-PF party switched the emphasis of their campaign of political intimidation away from white farmers to individual supporters of the opposition, the Movement for Democratic Change (MDC), ahead of next month's elections.
One MDC supporter was attacked with axes in Shamva, 55 miles north of Harare, on Monday night after attending a rally. He was approached by Zanu supporters and asked to produce the party card.
"He failed to do so and was beaten badly," said Moses Kufandiko, the MDC organising secretary for the area. David Mhaurwa died yesterday morning.
Another MDC supporter was killed on Monday night in the capital, Harare. He was working as a bouncer at a bar when two Zanu supporters approached and asked to come in. He refused them entry and when they noticed that he was wearing an MDC T-shirt they beat him to death with metal bars.
Another opposition organiser, Robert Mbuzi, died from gunshot wounds he suffered on Friday near Mhangura, 100 miles north-west of Harare.
Their murders bring the death toll to 12 in the past two months. Ten of the victims have been members of the MDC, which is posing a serious threat to the 20-year rule of president Robert Mugabe's party.
The other two were a farm foreman and a policeman who was killed because he was suspected of supporting the MDC. Two of the dead MDC members were also white farmers.
Police arrested five suspects for the murders yesterday - the first arrests since the most recent spate of killings and beatings began.
Morgan Tsvangirai, leader of the MDC, said political violence may be the price Zimbabwe has to pay to achieve democratic change. "This intimidation will continue," he said. "We believe violence against our supporters will not be scaled down until after the elections, whenever they are held. The MDC is aware of this burden and sacrifice. It will not deter our campaign. The elections are the real benchmark. They will determine where this country is headed. We shall pull through."
Mr Tsvangirai doubted whether a meeting in London later this week, between a Zimbabwe government delegation and the British government to discuss the land crisis, would offer a tangible solution.
"We believe the question is one of the future of Mugabe's government, and that cannot be settled by the London meeting. The violence at home has nothing to do with commercial farmers, it is a political equation," Mr Tsvangirai said.
With the scheduled time for the election fast approaching and the MDC maintaining a strong political presence, Mr Mugabe has stopped scapegoating white farmers and let the question of land reform take a back seat as his party's supporters have begun to target opposition party workers and the black labourers he fears will support them.
Many white farmers returned to their homes over the Easter weekend under local deals with squatters which ensured their safety, so long as they did not allow the MDC to organise on their property. Mr Mugabe's political opponents have accused him of attempting to stoke up racial hatred and revive the issue of land redistribution in order to divert the electorate's attention from the parlous state of the country and the unpopular war in the Congo. Inflation stands at more than 50%, unemployment is also high and foreign reserves have dwindled, while fuel shortages are widespread.
Mugabe is not due for re-election until 2002. But his hold on power has looked increasingly tenuous, particularly since he lost the referendum on constitutional change last month which would have allowed him to run for president for two more five-year terms.