Retired Mossad servicemen, the same as Russian, commonly become bodyguards.

Avi was the tycoon's last protection after Berezovsky lost a fortune in a series of scandalous law suites.

One of the tycoon's friends told The Daily Telegraph: "He thought after losing the case and all his money they wouldn't consider him worth killing", not specifying who those "they" were.

According to the tycoon's bodyguard, Berezovsky was alone at home from 10:00am to 3:00 pm on Saturday, while was running errands.

When the bodyguard returned he saw a number of missed calls on Berezovsky's phone.

The guard can now potentially become a suspect as he was the last to have seen Berezovsky alive.