A grief-stricken family has renewed calls for justice amid fears that a surgeon’s death in Syrian custody will be forgotten.
Dr Abbas Khan, 32, travelled abroad to help save children and women but was arrested with 48 hours of entering war-torn Syria in November 2012.
Dr Khan was tortured and beaten by interrogators and held in captivity until his death on December 16 2013, just days before his expected release.
He had been a research fellow at the Elective Orthopaedic Centre (EOC) at Epsom Hospital while working for the hospital trust between August 2011 and January 2012.
On Monday his brother Afroze Khan said: "Six whole months since our brother’s death we are no closer to the truth of what really happened to him.
"Abbas showed great courage and fortitude in the presence of tyranny and we do not want his story to be buried in Syria or forgotten in Britain.
"Abbas made a selfless act to help others with no regard to the risk to his own life. For this he was imprisoned, tortured and in an act of sheer cruelty murdered just when freedom was in sight.
"On this day we ask that Abbas’s sacrifice be not forgotten and that there be a ceaseless pursuit to grant him and his family justice."
His sister Sara Khan said: "The loss of my brother has left an indelible scar for us all and nothing can ever bring him back or help us recover from the pain we have suffered, however, this does not mean we will allow the perpetrators to walk freely and we will fight till justice is done."
Streatham MP Chuka Umunna said: "The treatment of my constituent, Dr Abbas Khan, who was tortured and eventually killed whilst in the hands of the Syrian regime, was a heinous act which should never be forgotten and for which justice is required.
"There seems to me no doubt that people within Syria know more than what they are saying now of what exactly happened to Dr Khan, who killed him, and who gave the order.
"Whilst the tragedy that engulfs the country could mean the path to truth and justice is longer and more arduous than most; that means only that we must not let up in our pursuit of justice."
An inquest into his death is ongoing.