Former Aide Says Obama Warned Trump About Flynn

But at least one former Obama official disputed that, saying Obama's concerns were not related to the firing of Flynn from the Defense Intelligence Agency but rather in the course of the investigation into Russian interference into the 2016 election.

Source : http://www.cnn.com/2017/05/08/politics/obama-trump-michael-flynn/index.html

Obama warned Trump about hiring Flynn
Obama explicitly warned Trump not to hire Flynn, former Obama aides say
Obama warned Trump about Flynn, former official says
Obama warned Trump about Flynn, former officials say
Obama warned Trump about Flynn, former officials say
Obama warned Trump about Flynn, former officials say
Obama warned Trump about Flynn, former officials say
Obama warned Trump about Flynn, former officials say