A British engineer murdered in the French Alps a year ago recorded all of his phone calls giving police "some very precise details."
Ten months after his brother's murder in the French Alps, Zaid al-Hilli has moved from witness to suspect.
Two British girls who survived the killings of their family in the Alps are to be interviewed by police as the search for answers continues.
French police have released a sketch of a man wanted for questioning in connection to the Alps murders of British-Iraqi Saad al-Hilli, his wife and her mother, in September last year.
A French cyclist was also shot dead. Mr al-Hilli's two daughters survived the attack on a remote road near Lake Annecy.
Investigators quoted on the Le Monde website stressed that attention should be paid to the dark or black helmet worn by the motorcyclist with an opening at the chin.
The brother of the British businessman murdered in the French Alps with his wife and mother-in-law has said in his first interview that he is not the killer.
Zaid Hilli, 54, who is on police bail following his arrest on suspicion of masterminding the murders 13 months ago, told the Sunday Times (£) that Saad al-Hilli grabbed him as they argued about their inheritance.
However, he denied any involvement in the shootings that killed Saad, 50, his wife Ikbal, 47, his mother-in-law Suhaila al-Allaf, 74, and Sylvain Mollier, a French cyclist. The al-Hillis’ daughters, Zeena, then 4, and Zainab, then 7, survived the attack.
“The French, I don’t trust them at all. My brother was killed there in that region and I am not going to take the risk. If they wanted to come over here, that’s fine,” he said.
One of the victims of the French Alps murders recorded all of his phone calls giving police "some very precise details", investigators said today.
British engineer Saad al-Hilli recorded all of his telephone calls and the audio files are in the process of being analysed.
Mr al-Hilli, his wife Iqbal, her mother Suhaila al-Allaf and French cyclist Sylvain Mollier were all killed in the attack on September 5 last year. The al-Hillis' daughter Zainab was shot in the shoulder and beaten, but survived.
French and British investigators held a joint press conference today, where Annecy prosecutor Eric Maillaud said: "The victim recorded all his telephone conversations. We therefore have some very precise details."
He added that although no charges have been brought in the case, police "have made great advances."
British and French police said they were "determined" to solve the murders of three al-Hilli family members and a French cyclist which took place a year ago.
Saad al-Hilli, his wife Iqbal, her mother Suhaila al-Allaf and Sylvain Mollier were all shot dead in the French Alps on September 5 last year. The daughters of Mr and Mrs al-Hilli survived the attack.
Mr al-Hilli's brother Zaid, who is due to answer police bail next month, was arrested on suspicion of conspiracy to murder amid claims he changed documents to ensure he inherited their father's inheritance.
Police said their main line of inquiry remains a row over inheritance, with Annecy prosecutor Eric Maillaurd saying: "This is being followed up actively."
Mr Maillaurd added that the two brothers "initially worked together to regain their father's property" in Iraq but differences between the men soon emerged, according to news agency AFP.
The brother of a British engineer who was shot dead with his wife and mother-in-law in the French Alps has been bailed after being arrested and questioned by police.
Zaid Hilli was arrested yesterday on suspicion of conspiracy to commit murder after officers uncovered evidence to suggest he doctored documents to ensure he inherited the estate.
Hilli, 54, has previously denied any feud with his sibling over an inheritance or involvement in the killings.
A police spokesman said: "The 54-year-old man who was arrested yesterday on suspicion of conspiracy to murder has tonight been released on bail until July 31 pending further enquiries."
Detectives investigating a multiple murder in the French Alps last September, including a British couple, have arrested the brother of one of the victims.
French and British police have been working together to find the killer of Saad Al-Hilli, his wife, his mother-in-law and a French cyclist.
ITV News Europe Correspondent Emma Murphy reports.
Sources on the French side of the team investigating the murders say it is a matter of asking questions of Zaid Al-Hilli on his feud with his brother, their father's inheritance and their father's money in Switzerland.
He is in custody as a result of moving from being a witness to a suspect. We are told they have no more elements of proof at this stage.
On Wednesday it was made very clear that Zaid Al-Hilli was not a suspect, although I was told "this could change at any time".
The brother of Saad Al-Hilli is being questioned by detectives investigating the killing in the Alps of Saad, his wife Ikbal, mother-in-law Suhalia al-Allaf and local man Sylvain Mollier.
Mr Al-Hilli's brother Zaid Al-Hilli, who is in his 50s and lives in Surrey, has previously denied any feud with his sibling over an inheritance. He was arrested by police at an address in Chessington.
Around 100 police officers in Britain and France are investigating the killing of the family on September 5 last year as they drove through a remote area close to Lake Annecy.
French investigators came to the UK and searched the al-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 Mr al-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.