Updated

Kenya's president says he is "deeply shocked" by the torture and killing of an election official who was crucial to next week's presidential vote.

Concerns are growing that the election again will face dangerous unrest.

President Uhuru Kenyatta said Tuesday on Twitter that investigations into Christopher Msando's killing should be allowed to "proceed calmly," and he warns against "careless speculation."

Msando was in charge of managing information technology systems at the electoral commission. He had publicly sought to reassure voters that the results of the Aug. 8 election would not be tampered with.

Hundreds of activists have marched peacefully to the electoral commission to protest the killing.

A former government official turned whistleblower, John Githongo, says there is plenty of reason to believe Msando's death is related to the election.