Former President Donald Trump said on social media Tuesday he received a letter notifying him he is the target of a Jan. 6 grand jury investigation. He later went after special counsel Jack Smith, calling him "deranged" and saying the investigation is a "disgrace." CBS News' Robert Costa reports from Washington. #news #trump #january62021 Each weekday morning, "CBS Mornings” co-hosts Gayle King, Tony Dokoupil and Nate Burleson bring you the latest breaking news, smart conversation and in-depth feature reporting. "CBS Mornings" airs weekdays at 7 a.m. on CBS and stream it at 8 a.m. ET on the CBS News app. Subscribe to “CBS Mornings” on YouTube: youtube.com/CBSMornings Watch CBS News: cbsn.ws/1PlLpZ7c Download the CBS News app: cbsn.ws/1Xb1WC8 Follow "CBS Mornings" on Instagram: bit.ly/3A13OqA Like "CBS Mornings" on Facebook: bit.ly/3tpOx00 Follow "CBS Mornings" on Twitter: bit.ly/38QQp8B Subscribe to our newsletter: cbsn.ws/1...