Updated

British police on Tuesday released on bail a suspect and brother of a murdered British-Iraqi man, Saad al-Hilli, who was shot dead along with his wife, mother-in-law and a French cyclist in the Alps last year.

"The 54-year-old who was arrested yesterday on suspicion of conspiracy to murder has tonight been released on bail until July 31 pending further enquiries," said Surrey police in a statement on its website.

Eric Maillaud, the prosecutor in charge of the case in France, told AFP Tuesday that the suspect Zaid al-Hilli was released at around 1800 GMT and faces a number of unspecified conditions in his bail terms.

He added that "no serious charges" had been laid against him and that "the investigation is continuing."

Zaid al-Hilli was detained on Monday in Surrey, near London, on suspicion of conspiracy to commit murder in what British police said was a "pre-planned arrest".

His brother Saad, Saad's wife Iqbal and her mother Suhaila al-Allaf were killed in the family's BMW estate car in a car park at a beauty spot near Lake Annecy on September 5 last year.

A French cyclist, Sylvain Mollier, was also gunned down, although investigators believe he was not a target and was just in the wrong place at the wrong time.

The al-Hillis' two young daughters survived the shooting, one of them by huddling next to her dead mother's body for hours until police found her.

Zaid al-Hilli was taken to a police station after the early-morning arrest in Surrey, where his murdered brother had also lived.