Bagaya and Nyanjura were arrested Wednesday as they attempted to launch thier book Is it the fundamental change? Unveiling the Hidden truth at the Constitutional Square in Kampala.
The two Makerere university students belong to the banned political pressure group Activists for Change (A4C) and Nyanjura is a member of Kizza Besigye's Forum for Democratic Change.
They had organised to launch the book on Wednesday to coincide with the first anniversary of A4C.
Police on Sunday picked up Bagaya from the university and interrogated him about the content of the book.
According to the authors, the phenomenon of dictatorship in Uganda cries out for extensive investigation in order to come up with a strategy and tactics to ensure political activism, social and economic development.
Their arrest of could make the hitherto-unknown publication popular.
Kampala Metropolitan Police spokes person Idd Ibin Senkumbi said the authors and two others defied police orders stopping them from launching the book at the Constitutional Square which he said was out of bounds.
He said the four are in custody at the central police station and will be charged with participating in unlawful society. If convicted they could face up to seven years in jail.
The government of Uganda last week banned A4C, which has been the mastermind of a series of protests in Kampala over increasing prices of fuel and commodities since April last year.
Attorney-General Peter Nyombi on 4 April 2012 issued a declaration of unlawful assembly in regard to the pressure group.