The federal investigation into the assassination of conservative activist Charlie Kirk has yet to find a link between the alleged shooter, 22-year-old Tyler Robinson, and left-wing groups on which President Donald Trump and his administration have pledged to crack down after the killing, three sources familiar with the probe told NBC News. > >One person familiar with the federal investigation said that “thus far, there is no evidence connecting the suspect with any left-wing groups.” > >“Every indication so far is that this was one guy who did one really bad thing because he found Kirk’s ideology personally offensive,” this person continued.