The brother of a British engineer shot dead with his wife and mother-in-law in the French Alps is being questioned over the alleged fabrication of his late father's will, local police said.
Zaid Hilli was arrested on suspicion of conspiracy to commit murder after officers uncovered evidence to suggest he doctored documents to ensure he inherited the estate, officials said. Hilli, 54, has previously denied any feud with his sibling over an inheritance.
Detectives searched his home in Chessington, Surrey, and were later seen leaving the property with a plastic box, a ladder and two bags.
Eric Maillaud, Annecy's public prosecutor, said police would now try to establish any link between the alleged fraud and the brutal attack which killed Saad and Ikbal Al-Hilli, Mrs Al-Hilli's mother Suhaila al-Allaf, and local man Sylvain Mollier.
"We know there was a dispute between the two brothers over their father's will," he said.
"There are a certain number of documents that suggest Zaid attempted to fabricate his father's testimony in his favour. It looks like he tried to take the fortune for himself. That did not work but we want to ask him questions about it."
Mr Maillaud said detectives were aware of the allegedly false documents from an early stage in the investigation.
The arrest is the first significant development in the inquiry following the attack on a remote mountain road close to lake Annecy on September 5. Around 100 police officers in Britain and France have been tasked with investigating the killings. French investigators travelled to the UK last year to search the al-Hilli family home in Claygate, Surrey.
Their inquiry has focused on three lines of inquiry: Mr al-Hilli's work, links to his native Iraq and his family. Reports of a dispute between the brothers emerged soon after the massacre and led Hilli to approach police to deny any suggestion of an argument over the will.
Ahmed Al-Saffar, the brother of Mrs al-Hilli's dead mother, issued a statement in the aftermath of the deaths to say both the al-Hilli and Al-Saffar families were heartbroken by the killings.