Assad

Major General Bassam Al Hassan is a former commander in the Republican Guards who was part of President Assad's inner circle.

During these conversations, he is said to have told investigators from the FBI and CIA that the now-ousted President Assad ordered the execution of missing American journalist Austin Tice.

Sources familiar with the conversations told the BBC that Al Hassan claims to have initially tried to dissuade President Assad from killing Mr Tice, but that he eventually passed on this order and that it was carried out.

Western intelligence sources familiar with the details of Al Hassan's claim that President Assad gave the order to kill Mr Tice are sceptical that he would directly give such an instruction, as he is known for having mechanisms for distancing himself from such actions.

Bassam Al Hassan was considered one of President Assad's most trusted advisors.