An arrest has been made in the unsolved murders of three British family members and a French cyclist who were gunned down in the Alps in 2012.

The prosecutor in Annecy, France, said a person had been taken into custody on Wednesday morning in relation to the investigation.

Saad al-Hilli, 50, his wife, Ikbal, 47, and her mother Suhaila al-Allaf, 74, were shot dead on a road near Annecy in eastern France on September 5, 2012.

Their two young daughters survived the horror, but 45-year-old cyclist Sylvain Mollier was also killed.

The bodies of Iraqi-born engineer Mr al-Hilli and his dentist wife, who lived in Claygate, Surrey, were discovered along with that of Mrs al-Hilli’s mother in their BMW on a remote forest route.

In a bizarre twist, Mrs al-Hilli’s previous husband, an American dentist named only as James T, died from a heart attack on the same day as the couple, but police said there was no link to the murders.

Suspects previously arrested in connection with the case include an Iraqi prisoner known as Mr S who was claimed to have said he had been offered “a large sum of money” to kill Iraqis living in the UK.

Mr al-Hilli’s brother, Zaid, was also arrested on suspicion of murder in 2013 but was later told he would face no further action after police found there was insufficient evidence to charge him with a crime.