South East Counter Terrorism Command said in a statement that it was aware of "recent reports in the media regarding a 20-year-old man from Oxford travelling to Syria and can confirm we are investigating".
"We can confirm a 55-year-old man and a 53-year-old woman, from Oxford, were arrested on suspicion of sending money to Syria which could be used for terrorism purposes and were bailed until February 17," the statement said without identifying them.
Meanwhile, the parents of Jack, John and Sally Letts, in their first TV interview since news of their son being in ISIS-controlled territory in Syria broke, denied allegations that their son had joined ISIS and said the money was for their son to buy a new pair of glasses.
"Even if you know he's in danger or can't see straight, what parent is not going to try get their child a pair of glasses if he can't see straight," John Letts told 'Channel 4 News' in an interview.
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"Your child is about to fall off a cliff and they (the police) are holding you back even though he's crawling forward to the edge and they won't let you help him.
The couple said there was no evidence their son had become an ISIS fighter and claimed the police have "put two and two together and made 10".
"Because I don't want a son who would do that type of thing... That is not the kid that I recognise," she added.
For the first time, the couple revealed during the television that Jack suffered a serious mental health disorder called Obsessive Compulsive Disorder (OCD) and they have been trying to convince him to come back home to Britain.
Jack Letts, who attended Cherwell School in Oxford, converted to Islam as a teenager and now goes by the name Ibrahim.
He left his home for Syria over a year ago.