The brother of former student leader Anis Khan, whose death had sparked large-scale protests across West Bengal, was attacked near his home at Amta in Howrah district with sharp weapons and was seriously injured, his family members said on Saturday.

Salman Khan was attacked late last night and is now under treatment in a hospital, they said.

His wife claimed that he was being threatened constantly and the police did not pay any heed to the family's plea for protection.

"Salman was maintaining pressure on the police for justice in Anis' death. Some local goons belonging to the ruling party (TMC) had threatened to kill him. We had informed the police about the threat several times, but they ignored our plea," his wife claimed.

Howrah Police when contacted confirmed that it had received a complaint from the family about the attack.

CPI(M) student wing SFI took out a protest rally in the city against the alleged attack demanding the arrest of the attackers of Salman Khan.

The protestors, who marched around the College Street area, blamed the ruling TMC for the attack.

A team of SFI and DYFI leaders went to Salman Khan's residence at Amta and assured the family that the CPI-M student and youth wings will stand by them and "fight for justice."

"We will march to Amta police station tomorrow (Sunday) to press for the arrest of Salman's attackers and police action against constant threat and intimidation to the family of Anis Khan," Pratikur Rahman, a SFI leader said.

Anis Khan was found dead near his home at Amta on February 13. His father Salem Khan had moved Calcutta High Court alleging that Anis Khan was thrown off from the second floor of the house by three men dressed like civic volunteers and a fourth person in police uniform who had come to his home.

He had sought an investigation by CBI.

Amid the widespread protests, a special investigating team was formed by Chief Minister Mamata Banerjee and the HC allowed it to exhume the body for a second post-mortem. In July the SIT in its final chargesheet submitted to a Howrah court ruled out murder and said the former student leader had died due to the fall.

It, however, held five police personnel, including the officer-in-charge of Amta police station guilty of negligence towards duty.