A police spokesman said Sunday the ongoing investigation into the death of the United People's Freedom Alliance politician has revealed a white van was used in the political assassination, Xinhua reported.

Muttulingam was shot and killed Saturday in the Moneragala District, an area just southeast of the Sri Lankan capital of Colombo, the state-run Chinese news service reported.

Muttilingam was vice chairman of the district's local council and worked as a medical practitioner there as well. He was shot while performing his duties at a hospital.

The region had been suspected as a potential focus of Tamil Tigers rebels, who reportedly are being hard-pressed by government military forces.

Government officials told Xinhua the increased military pressure on the rebel group has caused militants to attempt to disrupt the peace outside Sri Lanka's northern region.