Delhi Police registered a case against them on charges including trespassing, violating prohibitory orders, breaching a peace bond and obstructing a public servant from discharging official duties, sources said.
Officials said Ranka and Das had signed bonds undertaking to maintain peace for a year after they were detained during a protest in Delhi on Saturday.
The detentions came amid protests over alleged irregularities in the Special Intensive Revision of electoral rolls and the denotification of Jantar Mantar as a designated protest site.
Reacting to the development, CJP founder Abhijeet Dipke accused the government of crushing dissent. In a post on X, he said, "Ashu and Saurav have been sent to five days' judicial custody. Their fault? Unfurling the Tricolour at Jantar Mantar."
"Show some guts, @narendramodi. If you're so determined to crush dissent, have the courage to officially declare an Emergency instead of hiding behind these cowardly tactics," he posted.
CJP legal team head Ratna Singh alleged that the three had been brought to Parliament Street police station in a private van at 3 am and were not allowed to meet their lawyers until late at night. "Despite these illegal actions, their spirits are high," she wrote on X.
On October 11, Delhi Police Commissioner Anurag Kumar issued an order designating Ramlila Maidan, Burari Ground and CBD Ground as venues for protests and demonstrations, effectively removing Jantar Mantar from the list of designated protest sites.
The CJP criticised the decision, arguing that moving demonstrations away from the national capital's political centre would reduce the visibility of public dissent. The party is set to hold a meeting to decide its future course of action.