A British engineer murdered in the French Alps a year ago recorded all of his phone calls giving police "some very precise details", investigators said today, reports ITV News.
Saad al-Hilli, from Claygate in Surrey, 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, while her four-year-old sister Zeena lay hidden under her mother's corpse and was only discovered eight hours after the murders.
French and British investigators held a joint press conference today, a year after the shootings, to give an update on the case.
Annecy prosecutor Eric Maillaud said that although no charges have been brought in the case, police had "made great advances."
Zaid al-Hilli, the brother of Saad, is due to answer police bail next month after he was arrested on suspicion of murder amid claims he changed documents to ensure he inherited the family estate.
Mr Maillaud said the inheritance dispute was "being followed up actively" and remained a key line of the inquiry.
He said police were looking into the Baghdad property of the brothers' father.
Read more of this report from ITV News.