"During our interrogation of Biswas, we have found that the IS account holder was in touch with the ISIS combatant and he was an aide," Bengaluru Police Commissioner M N Reddi told reporters in Bengaluru.
Biswas was produced before a city court today and sent to judicial custody till January 16.
Biswas was arrested on Dember 13 under IPC section 125 (waging war against the Government of any Asiatic power in alliance with the Government of India) section 18 and 39 of Unlawful Activities (Prevention) Act and Section 66 of the Information Technology Act.
Reddi said police have gathered sufficient evidence to prove that Biswas supported ISIS and also his direct messages on his Twitter handle revealed that he encouraged people to join IS.
"We have sufficient evidence to prove he (Biswas) supported ISIS. Direct messages on his Twitter handle also show he encouraged people to join the terrorist outfit. He had been pro-actively tweeting," he said.
Police had launched a manhunt for Biswas after Britain's Channel 4 News had aired the report on the presence of ISIS Twitter Ideologue @ShamiWitness here and arrested him from a rented apartment in the city.
On the Bengaluru blast outside a restaurant here on December 28 that claimed the life of a woman from Chennai and injured three others, Reddi said police were waiting for corroborative evidence to ascertain if the sketches matched.
Until then, police wouldn't release them, he added.
On whether police saw any link with the 2005 IISc terror attack in which an IIT Professor from Delhi was killed by unidentified gunmen, he said, "it cannot be ruled out."
Asked whether the suspects would have visited Bengaluru before carrying out the blast, he said "the police did not have tacit information on that but the suspects had stayed in Hubballi, Yadgiri and Hosapete for four to five months."
Outlawed outfit SIMI's possible role has come under the scanner of investigators probing the terror attack. Chief Minister Siddaramaiah had said last week that some SIMI members who had escaped from a jail in Madhya Pradesh had visited Karnataka.