Indian police say they will file charges on Wednesday against a man identified as the sole surviving gunman from the Mumbai attacks in November.
The charge sheet against Mohammed Ajmal Amir Qasab and others is expected to run to thousands of pages.
Police say he and nine other gunmen carried out the attacks in which more than 170 people died.
The charges are expected to include one of waging war against India. He could face the death penalty if found guilty.
Mumbai (Bombay) police commissioner Rakesh Maria told reporters on Tuesday: "The charge sheet will be filed tomorrow [Wednesday]. We will file the charge sheet in a city court. It is a mammoth document."
Indian law requires charges to be laid in court within 90 days of detention. Mohammed Ajmal Amir Qasab was arrested on 28 November.
Media reports say the charge sheet may name suspects believed to still be in Pakistan as well as the 10 gunmen.
The BBC reports relations between India and Pakistan have worsened considerably since the November attacks.
India accused the Lashkar-e-Taiba group of being behind the attacks.
It has submitted a list of suspects to Pakistan and demanded they be handed over.
Pakistan and Lashkar have denied involvement. However, an investigation by Pakistan has found that at least nine attackers had sailed from Karachi to Mumbai in three boats in November.
Pakistan says it has indicted eight people, six of whom have already been arrested, and that any trials will take place on its soil.