THE family of a young Irish charity worker killed in Zanzibar have returned to Ireland after attending the first day of his alleged killer's trial, which was adjourned within hours of opening and is due to resume on 8 February.

Robert Stringer (26), from Newcastle, Co Wicklow, was found dead in August 2009 on a beach in Zanzibar, an island in the Indian Ocean off Tanzania. He had suffered head injuries and had also been mugged.

A local taxi driver, Othman Hamed Khamis, who had been driving Stringer around the island, has been charged with his killing.

Two weeks ago, the charity worker's parents, Keith and Josephine, as well as his two younger brothers, Peter (26) and Graham (24), travelled to Zanzibar to attend Khamis's trial. However, it was adjourned after hearing evidence from just one witness. "The family is back in Ireland. They are happy proceedings have started," Stringer's aunt Frances Stephenson said.

The first witness for the prosecution, Peter Minchin, a South African national, told the court in Zanzibar he had been celebrating his birthday on 5 August 2009, the night Robert was killed. Minchin said he had asked Khamis to drive Stringer to his home to join him and another seven guests at a party.

Khamis had been Minchin's best friend for 12 years, he told the court.

At about 5pm, everyone left Minchin's home, which is at Nungwi beach, and went to a local bar. The celebrations continued there until 1am.

"Before I went to sleep I said goodbye to Stringer and we agreed to meet the next day for further business discussions... I was shocked next morning to hear that he had been found dead," Minchin told the court.

It is understood police believe Khamis had two accomplices who have since fled the island. A signal from Stringer's mobile phone, which was stolen in the mugging, was picked up in South Africa shortly after his death.