Isis foreign fighters - go home or go to Guantanamo?

There are now hundreds of foreign fighters who joined the Isis "caliphate" sitting in jails in Syria with an uncertain future. They were all captured by the supremely efficient Kurdish-dominated Syrian Democratic Forces and they hail from all over the world, including the US, UK, Canada, Chechnya, Tunisia, Saudia Arabia etc etc. Great news that they have been taken off the battlefeld but now what to do with them? The obvious option is to send them back to their home countries and put them on trial. But here's the difficulty. To prosecute them, at least in places like the US, UK and Canada, there has got to be sufficient prosecutable evidence gathered from the battlefield to put them away for the rest of their lives. The UK government has very cleverly made stateless the two so-called members of the "Beatles" Isis execution squad, captured in January - cancelling their British passports. In other words, the Home Ofice doesn't want either of them back in the UK thank you, even though they were British when they left for Syria and turned into "alleged" monsters. This is a cowardly way of dealing with these people. They should be brought back and put on trial. My God, British and other newspapers have been writing about these individuals for years. There must be evidence around. What is not going to happen apparently is the Guantanamo option. The UK doesn't want them in Guantanamo, and the US doesn't want them in Guantanamo. So unless they spend the rest of their days in an SDP prison - without any guarantee that the SDP will be able to secure them properly - no one has a clue about where they should go. Not just the two ex-Britons but the rest of the bunch. In Iraq it was different because the Isis fighters captured there were all handed over to the Iraqi government authorities and thrown into prison where they will remain until they are put on trial and, I guess, face execution. The SDP is not a government, they are a well-trained militia. They can't be expected to keep foreign fighters in detention in perpetuity. And they can't hand them over to the Assad regime. The SDP and Assad don't communicate. Some decent legal brains need to get this one sorted out, otherwise I can see headlines in the future about Isis fighters escaping jail and disappearing. Meanwhile the UK govenment has to take responsibility for any of the British nationals now in an SDF jail, even if the Home Office has made them non-British passport holders.