At least five people were killed and around 60 wounded in the bombing in May of a new church building during a service to mark its official opening.
An explosive device was thrown into the church compound in Olasti, a predominantly Christian suburb of Arusha, on May 5. Senior church figures were in attendance for the inaugural service.
A Barnabas Fund contact in Tanzania said that radical camps in the country were teaching young Muslims that Christians must be killed or live as second-class citizens. He said that senior Christian leaders had reported details of these camps to the authorities, but no serious action had been taken against them.