I generally take people at their word.
Then don't...not on the internet. If a person's claim sounds outrageous then it probably is. If a person claims to "have sources" but fails to list them then it's probably false.
Why would anyone who is trustworthy with critical information even attempt to allude to such information and at the same time say "I can't tell you my source" or "I can't tell you anything more" unless they are frauds whose sole reason for those statements is to garner attention to themselves?