Zaid al-Hilli arrested on suspicion of conspiracy to murder Saad and Iqbal al-Hilli, Suhaila al-Allaf and Sylvain Mollier

This article is more than 7 years old

This article is more than 7 years old

The brother of a British engineer shot dead with his wife and mother-in-law in the French Alps last year has been arrested in Surrey on suspicion of conspiracy to commit murder.

Zaid al-Hilli, who is 54 and lives in Surrey, has previously denied any feud with his sibling over an inheritance.

Saad al-Hilli, 50, his wife, Iqbal, 47, and her mother, Suhaila al-Allaf, 74, were shot near Lake Annecy in the Haute Savoie in September. Their daughter Zainab, then aged seven, was shot in the shoulder and beaten on the head in the attack while another daughter, Zeena, four, escaped unhurt after hiding in the footwell of the family's BMW estate under the skirt of her dead mother for eight hours.

A passing cyclist, Frenchman Sylvain Mollier, 45, a father of three who appeared to have stumbled across the scene, was also murdered in the attack, which French investigators have suspected was a contract killing.

Surrey police, who have been working with French detectives, said in a statement: "Detectives investigating the deaths of four people near Annecy, southern France, in September last year have this morning, 24 June 2013, arrested a man on suspicion of conspiracy to commit murder.

"The 54-year-old man was detained at an address in Chessington, Surrey, at around 7.30am and is currently in police custody, where he will be interviewed.

"Saad and Iqbal al-Hilli from Claygate, Surrey, and her mother, Suhaila al-Allaf, who lived in Sweden, were found shot dead along with French cyclist Sylvain Mollier on a remote forest road in Chevaline on 5 September 2012.

"As part of the joint investigation team, which was established on 21 September last year, officers from the Surrey and Sussex major crime team have been working closely with the French authorities to progress a number of lines of inquiry.

"This pre-planned arrest is a result of these ongoing inquiries."

Police inquiries into the case have spread to a number of other countries including Iraq, the former Yugoslavia and Switzerland. The two girls are reportedly in the care of a foster family.

Around 100 police officers in Britain and France are investigating the killing of the family. French investigators came to the UK and searched the Hilli family home in Claygate, Surrey, in the wake of the deaths.

They said in September that they were investigating three lines of inquiry, focusing on Hilli's work, his family and links to his native Iraq.

Annecy's chief prosecutor, Eric Maillaud, said last year that there would be no "quick solution" in finding the killers.

Maillaud said: "We're investigating everything but it all takes a lot of time, trying to piece together the lives of all the people who have died, trying to perhaps understand a real motive, the real reasons for these killings.

"Perhaps if we can understand why they were killed we can work out who killed them, but at the moment there are many questions."