The Central Bureau of Investigation has filed a chargesheet against eight people in connection with the kidnapping and murder of a London-based non resident Indian businessman even as the agency has kept the investigations open to examine the conspiracy angle in the case.

The chargesheet was filed on Friday evening against eight people, belonging to Chakma tribe, before a designated court in Guwahati, who were charged with various sections of Indian Penal Code pertaining to kidnapping for ransom and murder as the agency alleged they had killed industrialist Protul Deb.

Those chargesheeted included Sardev Chakma, Krishna Medhar Chakma, Kalpuna Chakma, Roopdhan Chakma, Sahrdev Chakma, Batipura Chakma, Khegun Chakma and Raiput Chakma, agency sources said in New Delhi on Saturday.

During investigations, the CBI found that these people had kidnapped Deb along with his friend on March 17, 2004 and later killed him. They buried the body near a river bed after the police started tightening the cordon in search of the industrialist.

Ironically, the abductors had taken ransom of Rs 2.5 lakh from the family members of Deb on two occasions even after he was already killed by then.

Assam's Social Welfare Minister Gautam Roy, who is also the brother-in-law of the deceased, was also questioned by the CBI along with his son during the investigations, the sources said, adding that they had not been booked by the CBI as there was no evidence against them.

The minister's name surfaced after the complaint made by relatives of the deceased.

Deb, husband of Dolly Deb, elder sister of Assam Social Welfare Minister Gautam Roy, was kidnapped along with his friend Sadhan Nath on March 17, 2004 while they were on their way to Mizoram.

A resident of London [Images], he had unsuccessfully contested the last assembly elections as a Bharatiya Janata Party candidate against his brother-in-law.

His skeletal remains were recovered from Boncherra in Hailakandi near the Assam-Mizoram border, which were later brought to AIIMS for postmortem and DNA tests confirmed it was of the NRI businessman.