The demonstrators gathered at the GPO park in Lucknow and launched a tirade against the Samajwadi Party-led Uttar Pradesh government.
All India Congress Committee general secretary in charge of UP affairs Ashok Gehlot said the incident had projected the state government in poor light. He claimed the murder and similar such incidents in the recent past proved the UP Police was totally ineffective.
Uttar Pradesh Congress Committee president Salman Khurshid said the murder of a woman who stood up against people insulting her daughter-in-law was an indicator that it was difficult to protect the dignity of women under the rule of the present government.
There had been a simmering resentment over the crime since February 28 when Mehar Bhargava -- wife of a prominent Congress leader -- was shot and rushed to Delhi for treatment. However, the anguish surfaced only after she died in Delhi on Saturday.
Pressure is being mounted on the UP government with civil groups, students and women organisations pitching in through different forms of protests.
Bhargava was shot by miscreants in the busy Hazratganj area -- barely few yards away from the SSP residence -- when she objected to lewd remarks passed on her daughter-in-law.
She was partially paralysed following the bullet wound and breathed her last at a hospital in the national capital.
Chief Minister Mulayam Singh Yadav has assured speedy action against the prime accused.
Soon after Yadav's visit, the police suspended senior SI and Investigating Officer Dinesh Chandra Dubey and SI K M Rai.
Yadav also asked the IG, Lucknow, to ensure expedient action, which was followed by the arrest of K D Singh under charges of harbouring the assailants.
Dismissing allegations that the criminals were being protected, the CM had said, "The police is making all efforts... no one would be spared."
On the political front, the Congress party in UP Assembly, supported by BSP and BJP, walked out of the house when their demand for a CBI probe was rejected by the UP government.
Rejecting the demand for a CBI probe, state parliamentary affairs minister Mohd Azam Khan said two people had already been arrested in the case, while some others would be taken into custody soon.