It was at the very beginning of the investigation, and he thought the bar for this investigation, just under way, was totally different from Hillmailgate, which had been under investigation for a year, was then closed, and then Anthony's Weiner provided them with a bunch more emails, and thus uncertainty.

Comey said expressly that he thought it would have been wrong to "out" Trump campaign members based on the level of suspicion they had at that point. I see no reason not to take him at his word there.