They've said that he won't go on the exempt list as long as he remains unsigned. If any team actually signs him though, then that option is on the table again.
Is that a "read between the lines" message from the NFL? I don't know, but it wouldn't exactly be a big reach to interpret it that way.
In the meantime, they'll continue their investigation. Within that context, it's probably worth remembering that any form of witness harassment or intimidation is explicitly prohibited by the league's Personal Conduct Policy.