The NIA claims Swamy is linked to CPI (Maoist) activities and had a role in instigating violence.
Swamy was arrested from his home in Ranchi last month in connection with the violence in Bhima Koregaon near Pune in January 2018.
Lawyers and representatives of the five activists arrested on charges of plotting the Bhima Koregaon violence have slammed the government and the Maharashtra Police for fabricating evidence
Maharashtra police said that an email letter between Rona Wilson and a CPI-Maoist leader speaks of ending "Modi-raj" with a 'Rajiv Gandhi-type incident'.
Activists' arrest: Maharashtra Police claim to have unearthed larger conspiracy against security forces
Pune Police said that they would continue their investigation even though the apex court had ordered the five activists to be placed in house arrest.
Maharashtra Police wanted to take the activist to a Pune court in connection with a case relating to the Bhima-Koregaon violence of December last year.
The Supreme Court had directed that all five arrested activists be placed under house arrest till the next hearing of the matter on September 6.
Ambedkar also alleged that police have made contradictory claims about the violence at Bhima Koregaon near Pune in January.
Two Left-wing intellectuals said today the arrest of five prominent civil rights activists in police raids across several states showed that the BJP government was nervous about losing support.
The near-simultaneous raids against the five as well as four others were carried out as part of a probe into the violence between Dalits and the upper caste Peshwas at Koregaon-Bhima village near Pune
He said those raising voices against the government were NGOs and non-political organisations, but had their roots in the masses.
Bhima Koregaon violence: Three out of five arrested activists brought to Pune court, SC to hear plea challenging arrest
The three Left-wing activists were arrested yesterday by the Maharashtra Police and brought to Pune late last night.
The Maharashtra Police today raided the homes of prominent Left-wing activists in several states and arrested at least five of them as part of a probe into the violence in Bhima-Koregaon village.
The speeches at the conclave, held on December 31 last year to mark the 200th anniversary of the Koregaon-Bhima battle, had fuelled the violence a day later, they said.
Searches were carried out at the residences of poet Varavara Rao in Hyderabad, activists Vernon Gonzalves and Arun Ferreira in Mumbai, trade unionist Sudha Bhardwaj in Faridabad.