CHADEMA and human rights groups allege that security forces killed more than 1,000 people during the unrest, a figure the government has called exaggerated, without providing its own death toll.
The party said its deputy secretary general, Amani Golugwa, was arrested and listed by police alongside nine others as part of the investigation. The arrests follow prosecutors charging 145 people with treason earlier this week.
“The police force, in collaboration with other defence and security agencies, is continuing a serious manhunt to find all who planned, coordinated and executed this evil act,” police said in a statement.
The protests followed the electoral commission’s declaration of incumbent President Samia Suluhu Hassan as the winner with nearly 98% of the vote. She was sworn in on Monday. CHADEMA leaders have blamed the unrest on the exclusion of party leader Tundu Lissu and another prominent opposition contender from the ballot.
Authorities said those being sought include CHADEMA’s secretary general, John Mnyika, and the party’s head of communications, Brenda Rupia. CHADEMA accused the government of attempting to force confessions and said the treason charges were intended to undermine the party’s leadership.
African Union observers criticised the vote, reporting evidence of ballot-box stuffing, while the government dismissed such concerns and defended the election as fair.
Violent demonstrations began on October 29 in Dar es Salaam, Arusha, Mwanza, Mbeya, and other regions. Police said both public and private property, including bank teller machines and government offices, was damaged, and that people were harmed, without specifying casualties.