John Letts is asking the federal government to help free his British-Canadian son Jack Letts, an accused ISIS fighter who is being held by Kurdish forces in Syria.

In an interview with CTV’s Power Play, Letts said he’d be “the first to condemn him” if his son committed any criminal acts.

Jack Letts crossed into ISIS-held territory in Syria back in 2014 and was subsequently nicknamed “Jihadi Jack” by British media. He’s been imprisoned without charge for 18 months.

His father says his son is innocent and has written to members of Parliament and Global Affairs Canada in a bid to secure his son’s release.

Letts said his son had originally travelled to Kuwait to study Arabic and Islamic studies and converted to Islam. But Jack Letts eventually became bothered by the “horrors” of the Syrian civil war he’d seen playing out on TV and eventually travelled there.

“He was adamantly reading the Koran and saying it was the duty of every Muslim to help other Muslims, if they can,” Letts explained. Letts stressed his son had left Oxford, U.K., before ISIS had declared its caliphate so it hadn’t formed a lot of its borders.

But once Letts was in Syria, he learned that anyone looking to escape “couldn’t get out … because ISIS would chop your head off.” His father pointed to the incidents where those caught smuggling people out of ISIS territory were “crucified in the town square.”

Two weeks ago, Conservative Leader Andrew Scheer blasted the Trudeau government over reports that consular officials initiated contact with Jack Letts -- whom Scheer alleged was a "known jihadi fighter" -- about coming to Canada.

But Letts asserts Scheer was simply repeating false “stuff he picked up from the media.” Letts said he even offered to share all the information he had with Scheer.

According to Letts, Global Affairs Canada spoke to his son a year ago and is aware of the “terrible conditions” in the Kurdish prison camps, but said it’s too dangerous to move him.

On Tuesday, Public Safety Minister Ralph Goodale said people who leave Canada and enter into active war zones do so at their own peril.

“When you leave the comfortable confines of Canadian democracy and travel halfway around the world to go into a war zone and associate yourself with terrorists then you need to bear the consequences of that behaviour,” he said.

Goodale added Canada was not legally responsible to repatriate Letts or any Canadian in a similar situation.

“No offer of repatriation has been made and there is certainly no deal with the Kurds,” he said. “We need to be very sure we are not putting our diplomatic and consul officials at any risk.”

These comments were in line with what he had said last Thursday, when he also stressed Canadian security and intelligence forces were working in collaboration with their international counterparts to investigate all Canadians who travelled to Syria, "with the absolute determination to lay charges and to prosecute in every case."