1) Consensus from the intelligence community and fbi  that the russians waged a disinformation campaign that included illegal activities (dnc/podesta hacks) to get Trump elected.
2) Growing evidence of collusion between Trump campaign and russians.  A federal grand jury has begun issuing subpoena's http://www.cnn.com/2017/05/09/politics/grand-jury-fbi-russia/
3) New York attorney general is investigating Trump's business dealings, including violations of the enoulements cause and possible money laundering/RICO.
4) Trump has now fired three people involved in investigating him (Bharara, Yates and Comey).