Your comment supposes everything is known, like knowledge is some sort of digital environment of known, or not known, at the flip of a switch.
This is the reason for the demands of an investigation, free of political interference.  Your post summarizes why this is needed, its reasoning does not do anything to diminish the need.
If he has had no contact, good.  But, that has yet to be established, and there are overwhelming reasons to consider the investigation of that question as warranted, both in the seriousness of the threat, and in tangible evidence already available.