A British doctor who died while being held in custody in Syria was buried on Thursday, with his brother describing him as "our star".
Abbas Khan's family believe he was murdered, but the Syrian regime says he took his own life.
The British government has claimed that the 32-year-old orthopaedic surgeon was "in effect murdered" by the regime.
In emotional scenes after the funeral service at Regent's Park mosque in London, Khan's distraught mother Fatima could be heard crying: "Nobody help me, I love my son. I am the loser. I'm the failure."
She said: "I beg everybody. I touch everyone's feet. Please give me my son."
His brother Shahnawaz Khan told the packed service: "Last night I sat down to undertake the morbid task of writing a eulogy for my brother."
He said: "My brother, to us, was our star. His star shone on our family."
Abbas Khan was captured in November last year in the wartorn city of Aleppo after entering Syria from Turkey without a visa to help treat victims of hospital bombings.
He was about to be released when his family were told of his death.
His body was escorted out of Syria on Saturday by the International Committee of the Red Cross and returned to family members waiting in Lebanon.
He leaves behind wife Hanna, 30, son Abdullah, six, and daughter, Rurayya, seven.
The family's lawyer, Nabeel Sheikh, said an inquest into the doctor's death would open in London on Friday.
He said the idea that Khan committed suicide was "inconceivable".
The inquest will consider the results of a post-mortem.
The family have accused the British government of failing to do enough to secure Khan's freedom.
But British officials said they had "consistently sought" consular access to him, both directly and through other countries.
Prime Minister David Cameron wrote to Khan's mother Fatima on December 20, calling his death a "sickening and appalling tragedy".