The 54-year-old brother of a British engineer killed along with his family in the French Alps has been arrested on suspicion of murder.
Iraqi-born engineer Saad al-Hilli, his wife, mother-in-law and French cyclist Sylvain Mollier were found shot dead near Annecy in September last year.
The Al-Hilli's four-year-old daughter Zeena lay undiscovered under her mother's corpse for eight hours after the shooting, while her seven-year-old sister Zainab was found with serious injures after being shot and beaten.
Mr Al-Hilli's brother Zaid Hilli, who is in his 50s and lives in Surrey, has previously denied any feud with his sibling over an inheritance.
Surrey Police said the suspect was detained on suspicion of conspiracy to commit murder. He was held at an address in Chessington at around 7:30am "and is currently in police custody where he will be interviewed".
Surrey Police set up a Joint Investigation Team to work with French police on solving the brutal murders.