https://www.recode.net/2017/10/18/16497682/facebook-messenger-russia-trump-clinton-presidential-election

A top Facebook executive admitted Wednesday that Russian agents had used the social network’s popular Messenger platform to interfere in the 2016 presidential election.

Facebook Messenger boss David Marcus disclosed that a “very small” number of the 470 accounts active in the Russian interference campaign were using Messenger to communicate with their users.