Gunning for Badals, Sidhu seeks their excommunication
Sidhu submitted his letter at the Akal Takht Secretariat in Amritsar on Friday.
He alleged that the Badals had "misused" Sikh institutions to further their political motives.
Sidhu also claimed that the Badals had connived with controversial Dera Sacha Sauda sect chief Gurmeet Ram Rahim Singh to get him pardoned by the Akal Takht in 2015.
The Akal Takht had issued a 'hukumnama' (edict) in 2007 against the sect chief for donning an attire similar to that of the 10th Sikh master, Guru Gobind Singh.