WhatsApp co-founder joins call to #DeleteFacebook as fallout intensifies

Brian Acton adds his voice to Cambridge Analytica backlash, as US agency said to be investigating social network's mishandling of data

Facebook's troubles entered a fourth day with a rising chorus of people - including the co-founder of WhatsApp - joining the #DeleteFacebook movement as the Federal Trade Commission was reported to be investigating the company's handling of personal data.