Psychopaths are willing to manipulate those around them by deception — tricky, if they’re in charge and they have the human resources department in their pocket to cover their ass.

Here’s my favorite bit, from John Hancock, a social scientist at Stanford.

Having a psychopath within a company can lead to poor employee retention, said Hancock, referencing FBI research that found that departments managed by psychopaths decreases productivity and morale in the team.

Eight to 14 people could be lost because of one psychopath. That’s the real cost of having something like that in your organization, especially if there’s an HR cover-up.

You don’t say.

Anyway, if you do happen to work for someone who you think might be a psychopath, the panelists had some advice for what to do. Psychopaths are apparently very good at speaking face-to-face because their charm and their charisma cast a very powerful spell. Non-verbal communication works best.

Psychopaths also find it difficult to modulate their language for different settings for example a private message versus a public post. Because they are more interested in themselves than others, they tend to refer to other people a lot less than non psychopaths.

This means that text-based communication is a much better way to communicate with someone you suspect is a psychopath, since it strips away their non-verbal distractors, such as charm and confidence.

To defeat the psychopath, write them an email, I guess.

This article originally appeared on The Billfold.

Megan Reynolds is a writer and editor focusing on pop culture, digital culture and entertainment with bylines in Racked, Vulture, TheBillfold, the FADER, Gawker, Adequate Man and more.