The family of a young charity director stabbed to death in Washington DC said it will take a lifetime to come to terms with his murder.
Jack and Karen Senitt, of Pinner, north London, said the brutal death of their eldest son Alan, 27, has left them "devastated".
In a statement they said "it will take us a lifetime to come to terms with our tragic loss".
They added: "We under-stand that it is 'a mugging gone wrong' and that the gang involved has already been apprehended.
"We are all devastated by our loss but have been comforted by the many calls from family, friends and other well-wishers.
"We would also like to thank all those people in the States who have assisted us in the aftermath including the vice consul and his staff and the local rabbi.
"We have lost a much-loved son and brother. The Jewish community as a whole has lost one of its bright young leaders and the wider world has lost a champion of peace and goodwill."
Mr Senitt, a former member of the Board of Deputies of British Jews, was on an extended visit to the United States capital.
Police said he was set upon by a gang as he returned home with his girlfriend in the Georgetown area in the early hours of Sunday.
A spokesman for the Metropolitan Police Department of Washington DC said several people were expected to appear before a court today in connection with the death.
He declined to reveal further details, but it has been reported that two men, a youth and a woman have been arrested and charged with murder.
News of his death brought a flood of tributes from those who have worked with the political activist and former charity director. Lord Janner, vice president of the World Jewish Congress, said he had worked with Mr Senitt for the past year and they had travelled together.
He said: "It's awful, a horrendous shock. This man was bright, young and had just got a fascinating job.
"He was a great leader and this is a tragedy, an absolute tragedy, and everybody I know is just choked."
Lord Janner added that Mr Senitt was about to start working for former Virginia governor Mark Warner, touted as a Democrat candidate in the 2008 United States presidential elections.
Jonathan Levy, chairman of the Union of Jewish Students, said Mr Senitt led the Union with "distinction and pride".
He said: "Alan will be remembered, with a smile on his face, as someone who valued the opinion of youth and cared deeply about the British Jewish community."
Danny Stone, who succeeded Mr Senitt as director of the Coexistence Trust, an organisation that works with Muslim and Jewish political leaders, said he was an "inspiration".
Speaking of his political career, he said: "I am sure he would have been brilliant.
"He wanted to be involved in politics and he was so good at it."
Jeremy Newmark, chief executive of the Jewish Lead-ership Council, said: "Alan became a true friend of those that he worked with.
"He was an outstanding and passionate advocate for Israel, whilst articulating a message of tolerance and co-existence."
Mr Senitt graduated from Birmingham University with a first in community studies and had recently completed a masters in diplomacy at the School of Oriental and African Studies in London.
He also worked for the All-Party British-Israel Parliamentary Group and had stood as a Labour candidate for the Edgware ward in north London in the May elections.