The Met Police has taken the unprecedented step of appealing to Facebook users in Yemen to help trace a man suspected or raping and murdering Martine Vik Magnussen.
The force has repeatedly appealed for Farouk Abdulhak to return to the UK to face questioning over the the Norwegian student's death.
Its calls however, have gone unanswered and now, on the sixth anniversary of the brutal attack, the Met has posted an advert on Facebook to specifically target users in the Yemen to come forward with information.
The British Embassy in Yemen will also run an appeal on their Facebook page and send out related tweets.
Officers have worked closely with the Foreign & Commonwealth Office, however diplomatic attempts to arrange for his return to the UK have so far been unsuccessful.
Farouk has also reportedly recently got married in Yemen, a strong signal that he has no intention of returning to the UK.
Petter Magnussen, Martine's father, said: "Farouk Abdulhak is denying our family any closure by not taking his responsibility seriously, choosing not to return to the UK where the crime took place.
"He seems to be untouched by the simple values of respect, dignity and tolerance that are expected in any civilised society.
"These past six years he has continued to build his life in the Yemen showing no remorse or common decency.
"Our daughter would have been 29 in February this year and not a day goes by where she isn't foremost in our thoughts. We miss her every hour of every day."
Martine Vik Magnussen, who lived with friends in Westminster, had been out with her flatmates and fellow students in central London on the evening of 13 March 2008.
She was last seen by her friends at Maddox nightclub between 2am and and 3am.
She is believed to have left in a cab with Farouk Abdulhak, a fellow student at Regent's Business School who was known to socialise with the Norwegian and her friends.
Magnussen was subsequently reported missing to police by friends on 15 March sparking a hunt for her that ended when officers discovered her partly-concealed body on March 16, under rubble in the basement of the privately-owned flats.
A post-mortem examination gave the cause of death as compression to the neck.
The inquest into Magnussen's death at Westminster Coroner's Court on 24 November 2010 recorded a verdict of unlawful killing.
Detectives formally named 21-year-old Farouk Abdulhak as the prime suspect they wanted to speak to in connection with Martine's murder and rape.
Detectives have made numerous appeals for Mr Abdulhak to return to the UK so that they can speak to him about Martine's death.
It is known that Mr Abdulhak left the UK on a flight to Cairo on the afternoon of 14 March and from there it is believed he travelled to Yemen.