The 14-party-led ruling alliance has demanded trying Tarique Rahman after bringing him back home.
According to its leaders, Tarique, the senior vice-chairman of the BNP, is conspiring to destroy democracy and oust the government staying in London.
On Tuesday, Tarique attended a party meeting in London. He recently performed Omrah with his family.
They said he went abroad giving undertakings.
There are specific allegations of corruption against him, and he is absconding in the eyes of law, they added.
The alliance leaders made the demand from a meeting at the Awami League party president’s Dhanmondi office on Thursday, presided over by Suranjit Sengupta.
Tarique, the elder son of BNP chief Khaleda Zia, has been staying in London for treatment since he left the country in 2008 after being released on bail. He faces 14 corruption charges against him.
He was arrested during the army-backed caretaker government in 2007 and left the country on September 11, 2008.