Tundu Lissu, a lawyer and human rights advocate who survived a previous assassination attempt in 2017 when he was shot 16 times, was arrested in April 2025 and remains detained on 'politically motivated charges of treason'.

Lawyers for Tanzania's imprisoned opposition leader, Tundu Lissu, have called on donor countries to suspend aid to the country's government because of "credible reports" of an attempt to poison Lissu while in custody.

The law firm Amsterdam & Partners LLP, international counsel for Chadema -- the main opposition party, which Lissu leads -- said it was alarmed by the reports of the attempted poisoning.

"The attempt, first brought to light by Chadema party officials, marks a chilling escalation in the systematic persecution of political opposition figures under the administration of President Samia Suluhu Hassan," said the firm.

Robert Amsterdam, founder and managing partner of the firm, said, "The latest attack on my client is not an isolated act, but part of a broader campaign to silence and destroy the political opposition in Tanzania.

"From fabricated treason charges, unlawful detention and denial of legal access, to the targeting of opposition supporters and foreign activists, the Tanzanian government has crossed every red line of democratic legitimacy....