The Signal:

Tyler Robinson — the 22-year-old accused of assassinating conservative firebrand Charlie Kirk — is refusing to cooperate with investigators even as he sits on special watch inside a Utah jail. Meanwhile, President Donald Trump is blasting the “radical left” and warning that “a lot of people are already under major investigation” over Kirk’s shocking death.

Robinson was arrested Friday in connection with Kirk’s shooting death at Utah Valley University earlier in the week. Officials say the 31-year-old conservative activist was gunned down in the neck while debating students, a brazen political assassination that has sent shockwaves nationwide.