Kolkata, Apr 6 (IANS): Family members of SFI leader Sudipto Gupta Friday expressed disgust over West Bengal Chief Minister Mamata Banerjee dubbing his death in police custody as a "petty and small" matter. Asserting that the youth was "murdered", they also demanded a CBI probe.

"This is murder. The bus driver has reportedly said that he (Gupta) was forced out of the vehicle and beaten up. There were so many injury marks on his body. The truth can come out only if there is a CBI enquiry," Gupta's elder sister Sumita Sengupta told the media after meeting Governor M.K. Narayanan at the Raj Bhavan.

Flaying Banerjee, who had told reporters in Bangalore Thursday that Gupta's death was an "accident" and "a petty matter" and "small matter", she said: "Our chief minister does not know how to react to such situations Would she have made a similar comment had my brother been a Trinamool Congress worker?"

The SFI leader's father Pranab said Banerjee should step down from her chair for making such a comment.

"We have no faith in her (Banerjee), otherwise we would not have come here to meet the governor," said Pranab adding that Narayanan listened to their demands but did not made any comment.

Leader of the Opposition Surya Kanta Mishra, who met family members at their residence and then accompanied them to the Raj Bhavan, said they had "no faith in the state police" and wanted either a judicial inquiry or an probe bythe Central Bureau of Investigation (CBI).

Gupta, an activist of Communist Party of India-Marxist (CPI-M) affiliated Students Federation of India (SFI), died in police custody Tuesday after he took part in an agitation.

Left activists said Gupta was "mercilessly beaten" while he and other students who had staged a protest seeking elections in colleges, were being taken in a bus to the Presidency Correctional Home.

However, Joint Commissioner of Police (headquarters) Javed Shamim said soon after the incident that 24-year old Gupta died after his head hit a lamp post.

On Thursday, Shamim said the probe was still on, but the preliminary post-mortem findings indicate his body and head hit a "blunt, stationary" object before falling on a rough surface and that there were no injury marks from "laathi (baton) or rod or glass".