Complex sentence: In Syria, he was allegedly hired as a "government advisor"--with some suggesting he was advising the Syrian dictatorship on torture and repression techniques, some dating from his time as an SS torturer.
Split into simpler sentences: In Syria, he was allegedly hired as a "government advisor". The exact nature of his work is unknown, but it is believed he advised the Syrian dictatorship on torture and repression techniques, some dating from his time as an SS torturer.