UPDATE 3-U.S. senators accuse Yahoo of 'unacceptable' delay in hack discovery
September 27, 2016 at 13:41 PM EDT
WASHINGTON, Sept 27 (Reuters) - A group of Democratic U.S. senators on Tuesday demanded Yahoo Inc explain why hackers' theft of user information for half a billion accounts two years ago only came to light last week and lambasted its handling of the breach as "unacceptable."