"I don't know about his arrest. His phone is switched off. Now we have decided to go there," M Biswas who lives in the eastern fringe of the city said.
The police has not contacted him, he said.
The senior Biswas said he did not believe that his son had any link with ISIS. "One reporter asked me about it last night. Then I contacted him and inquired. My son said he did not understand how it has happened. He said that his internet account is hacked. I don't believe that my son has any link with ISIS," he told a TV channel.
Asked if he know that his son used to tweet in support of ISIS, he replied, "I don't know. But he told me that some people came to him from Channel 4".
On whether he supported ISIS, the senior Biswas said "I don't know what is ISIS. There is no question of supporting it".
Karnataka Director General of Police L Pachau told reporters in Bengaluru that Mehdi Masroor Biswas had 'confessed' he was handling the pro-jihad Twitter '@ShamiWitness' and he was particularly close to English-speaking ISIS terrorists.