The family of a Jewish student who died in Germany under suspicious circumstances seven years ago are demanding answers now that his inquest has been indefinitely adjourned.

Jeremiah Duggan, from Golders Green, north west London, was found dead, aged 22, on a highway near Wiesbaden, Germany, in March 2003, while attending a youth event organised by the far-right LaRouche group.

German police ruled that his death was suicide but a British coroner rejected the verdict in November 2003 after the Metropolitan Police testified that the LaRouche movement was a "political cult with sinister and dangerous connections".

Earlier this year, Lord Justice Elias in the High Court granted Jeremiah's mother Erica a new inquest, and said that fresh evidence showed that Jeremiah's death may have occurred elsewhere and the accident was "stage managed" to look like a road accident.

In June an inquest was officially opened at Barnet Coroners' Court and immediately adjourned after the coroner ordered that the new material should be given to the police, with the request that they take up enquiries, but the family have heard nothing since.

Mrs Duggan said: "It is shocking that it's taken five months and nothing has been done.

"If the police won't help us then not only have I been obstructed in Germany but I have also been let down by my own country. I think the British police are dragging their heels.

"The police are reviewing the files but they need to go to Germany to find the answers to questions which have been tormenting us."

Mrs Duggan wants to know the full circumstances surrounding Jeremiah's death, whether his injuries showed he was run over by cars or beaten around the head and what the activities of the LaRouche organisation were at the time.

Mrs Duggan is now taking the state of Germany to the European Court of Human Rights for violating Article Two of its constitution, by not properly investigating the circumstances surrounding her son's death.

Chief Rabbi Lord Sacks has backed the need for a full inquiry.

"I very much support a second inquest," he said. "There are sufficient doubts about the circumstances of Jeremiah's death to make a further and fuller inquiry appropriate and necessary."