Speaking to media, KM Ashokan, however, said that it would be established only when Supreme Court rules that.
"I do believe that he is (terrorist), but it is upto the court to decide... it would be established only when court says that. Nothing will work out if we say that he is a terrorist..we have got some evidences..but the court should pronounce it," Hadiya's father said.
When asked whether he would stop Jahan from meeting his daughter, Ashokan said whatever he will do, will be in accordance with law.
Earlier on Monday, the top court had freed Hadiya from her parent's custody and sent her to college to pursue her studies.
Hadiya, a Hindu by birth was converted to Islam after marrying Jahan.
The apex court has been hearing Hadiya's case after Jahan approached the top court following his marriage was annulled.