Ex-boss of MtGox bitcoin exchange arrested in Japan over lost $390m

French-born Mark Karpeles held in connection with the disappearance of hundreds of millions of dollars worth of the virtual currency

Mark Karpeles, the former head of defunct bitcoin exchange MtGox, has been arrested in Japan, and is reportedly to be questioned over the 2014 disappearance of nearly $390m (250m) worth of the virtual currency.