City police would soon file a supplementary chargesheet in the 26/11 Mumbai attacks case, describing LeT operative Sayed Zabiuddin Ansari alias Abu Jundal as one of the main conspirators who was briefed about the terror operation four months in advance by his bosses in Pakistan.

In the chargesheet, which is expected to be filed in a fortnight, the investigators would mention that Jundal, who had completed first year Masters of Arts in Hindi (MA-Hindi) course from Beed, was given a task of teaching Hindi to the arrested terrorist Mohammed Ajmal Amir Kasab and nine others, a senior crime branch officer told agencies.

The terrorists were taught Hindi so that they could speak in this language at the time of terror strike, in a bid to divert the attention of Indian security agencies.

The chargesheet would also disclose face-to-face interaction of Kasab and Jundal inside the high security Arthur Road Jail, where the lone surviving attacker is lodged, the officer said.

It would also comprise of Jundal's confession wherein he is understood to have given a deep insight into Lashkar-e-Taiba's role in the 2008 Mumbai terror strike, the officer said.

"We will file the supplementary charge sheet by October 20," the official said, adding that, "final touches are being given to it."

The chargesheet would also dwell upon how 30-year-old Jundal had issued instructions to two terrorists holed up inside Nariman House, a Jewish outreach centre, during the attack from a control room set up in Karachi.

It would also mention that his voice had been intercepted by intelligence agencies, the police officer said.

The voice samples of Jundal, who is a prized catch in the case, was sent to match with the voice that had been intercepted by the intelligence agencies during the attack.

However, forensic lab is yet to submit a report on this. The charge sheet would also mention that in August 2008, a group, including Jundal, was informed by LeT top members about the 26/11 operation. In the group, each one was given different tasks. Jundal was told to teach Hindi to the attackers.

A native of Beed district of Maharashtra, Jundal was taken into custody by Mumbai Police after he was brought here from Delhi where he had been arrested following his deportation from Saudi Arabia in June this year.

On July 21, Mumbai Police arrested Jundal in the 26/11 Mumbai terror attacks case. The mayhem unleashed by Kasab and nine others in Mumbai had left 166 dead and many injured.

According to police, Jundal was impressed by tenets of Ahle Hadees who 'adhere to the pristine teachings of Islam as enshrined in the Holy Quran and Sunnah'.

Later, in 2003, he subscribed to the ultra-conservative Hadees sect.

In 2005, Jundal started leaning towards terror activities as he came in contact with Aslam Kashmiri, a known militant commander currently in the custody of Delhi Police after his arrest in 2009, the official said, adding that Jundal met Kashmiri through Mohammed Amir Shakeel Ahmed, behind bars in connection with the 2006 Aurangabad arms haul case in Maharashtra. In 2005, Jundal had been to Nepal.

After the 2006 Aurangabad arms case, he escaped to Nepal via Kolkata. From there, he had flown to Pakistan using a fake passport, police said.

Jundal had undergone trainings called 'Daura-E-Aam' and 'Daura-E-Khas' in 2006 at terror camps of LeT in Pakistan.

He had also done odd jobs like working as electrician at construction sites in Pakistan, police said. He had been to Pakistan in the fake name of Saeed and his escape journey to the neighbouring country was assisted by two LeT operatives in India in May 2006.

The 26/11 key handler was also shown arrested in other cases in Maharashtra like the arms haul case, the 2010 German Bakery blast and the plan to attack Nashik Police Academy.

Following a Nashik Court order recently that Jundal, who was in custody of Maharashtra police, be produced before Tees Hazari court in Delhi in a case of conspiring to carry out terror attacks in India, he was taken to the national capital.