Interesting that one reason for rendition is that it is thought that it is not illegal to use information obtained through torture as long as someone else did it! While all this was going on US human rights groups were rightly lambasting Uzbekistan for its human rights record including boiling opponents alive.
These are a couple of snippets from a UK diplomat's article who served in Uzbekistan. The whole article is available here. There is a you tube video available here.
I falsely presumed, that these people they were bringing in and handing over to the Uzbek security service were Uzbeks who had been captured elsewhere and brought back to Uzbekistan. I did not realize that in fact they were of many other nationalities and were being handed over in order to be tortured. That they were being tortured I knew. That Uzbekistan was a destination for the extraordinary rendition system from all over the world I really didn't quite realize at the time. We now know, following, for example, a Council of Europe investigation, that 90 percent of the airplanes that stopped at the famous secret prison in Poland had Tashkent as their next destination. I complained back to London. I said we're getting this intelligence from torture
..... our legal advisers had decided that under the United Nations Convention Against Torture, it is not illegal to obtain or use intelligence gained from torture, as long as we didn't do the torture ourselves