The Commission promptly constituted a team to probe the matter and assured "urgent" redressal of the complaint, party Politburo member Brinda Karat, who led the delegation to the NCW over the issue, said.
Karat also attacked Mamata Banerjee-led government in the state over the issue, saying it is guilty of "blatant" violation of all standards to treat those in custody.
According to a memorandum the delegation submitted to NCW chairperson Lalitha Kumaramangalam, the four activists were arrested along with others on March 9 after they took part in a protest against alleged scam in appointments in primary schools.
The four activists attached to CPI(M)'s Students' Federation of India and Democratic Youth Federation of India were remanded to police custody until March 14.
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The quartet was taken to the jail at Alipore Women's Reformatory. Instead of being treated as political activists, they were subjected to illegal custodial torture, the CPI(M) claimed.
"They were stripped and searched which consisted of highly objectionable groping of their bodies.
"All through they were subjected to filthiest sexist abuse by women police personnel. The women personnel responsible also made it clear they were acting on orders from above," the memorandum claims.
"Is it not a fact that even with a woman Chief Minister in the state, human right violations have been increasing by leaps and bounds?" she asked.
The quartet reportedly got bail on March 14 from a Kolkata court.