Bangladesh’s military-backed government on Wednesday released the elder son of Khaleda Zia, former prime minister, with an eye toward securing her party’s participation in parliamentary elections planned for December.

Tarique Rahman, who was jailed in March 2007 in one of the highest-profile arrests of the government’s anti-corruption drive, is to fly abroad to receive medical treatment. His brother, Arafat Rahman Koko, was released in July “on humanitarian grounds”.