As we first reported, lawyers for Kris and Myla were jawboning Friday … Kris’ lawyers were trying to get her to sign a non-disclosure agreement. 

As for why they want to muzzle her, sources connected with Myla say she has emails, texts and other documents chronicling their relationship that could hurt Kris if they became public. 

Sources connected with Kris say … Myla threatened that if she didn’t get money she would “ruin” Kris. We’re told the two sides could not reach an agreement, and that’s when Kris’ people decided to take it to the FBI.

Our Kris sources would not say whether the alleged extortion was in person, over the phone, via email or text, but we’re told it is in some electronic form that would give the FBI jurisdiction to investigate the extortion allegation.

We reached out to Myla … so far, no word back.