Maqbool Chaudry, who knew Raqib from a mosque in Aberdeen, said he believed he was "led astray" when he moved away from the Scottish city.
"I feel really sad and sorry for him," Mr Chaudry told ITV News.
"I think it's a waste of a young life, especially when you know somebody that well, it's really shocking because will he ever get back in the community, the society? I don't think so.
"I think he got mixed in with the wrong crowd when he was down south. They led him astray."
Leaders of a Cardiff mosque, attended by 3 young men who are now fighting in Syria, say they had nothing to do with their radicalisation.
The Home Secretary has told ITV News that young women have left Britain to fight for the extremists group ISIS in Syria and Iraq.