Detectives investigating the murder of a British engineer and his family in the French Alps have ruled out a link with the death of his wife's secret ex-husband, who died In America on the same day.
Saad al-Hilli 50, his wife, Ikbal, 47, and her mother were shot dead along with a French cyclist on a forest road near Annecy in eastern France almost two years ago.
The Surrey couple's two young daughters survived the attack which has so far gone unsolved.
As police continue to search for a motive, it emerged that Ikbal al-Hilli was briefly married to an American dentist in 1999 without the knowledge of her family.
Prosecutors confirmed that the man, identified only as James T, died of a heart attack in Mississippi on the day of the killings in September 2012- but say they are not linking the deaths.
Police arrested Mr al-Hilli's brother, Zaid and a 48-year-old man separately in connection with the killings but both were later released without charge.
A train travelling through the French Alps was left dangling for hours after being derailed by a fast-falling boulder.
Two people were killed and nine injured after the so-called Train of the Pines was hit by a boulder just outside the town of Annot.
The mayor of the town Jean Ballester said the rock fell with "an extraordinary force".
A 54-year-old man was arrested in Surrey today in connection with the murders of Saad and Ikbal Al-Hilli, Mrs Al-Hilli's mother Suhaila al-Allaf, and cyclist Sylvain Mollier, who were all shot dead near Annecy, in the French Alps in September last year, Surrey Police said.