Complex sentence: The TRC found that the use of torture by MK was "routine"--as were executions "without due process" at ANC detention camps, particularly in the period of 1979--1989--though torture was not official ANC policy.
Split into simpler sentences: The TRC found that the use of torture by MK was "routine", as were executions "without due process" at ANC detention camps. This was particularly true in the period of 1979--1989, although torture was not official ANC policy.