The body of a British doctor who died while in government custody in Syria has been returned to the U.K. for a post-mortem examination.

Abbas Khan, a surgeon from London, died just days before he was apparently due to be released from Syrian government detention. His family says the Syrian government is responsible for his death, and a senior British official has also said Khan was "in effect, murdered."

Syrian authorities say the doctor committed suicide — a notion the family rejects.

The 32-year-old was captured in November last year after he entered Syria to work in a hospital.

A lawyer for Khan's family said the doctor's body was to be transported to a coroner's court in London on Sunday for a post-mortem.