[MaDeuce]

The laptop is really a bit of a red herring. If the person is the sort that would be inclined to retaliate against the company, they could have taken a copy of the pii whether or not the laptop was in the picture.

You could offer them payment for signing a severance agreement. You would do this in recognition of their significant contributions to date. The agreement would reiterate that they are bound by their existing NDA, explicitly state that they have fully deleted any company info/files that they may have had in their possession, acknowledge that disclosure of any private company info could have significant negative impact on the company, and could possibly include non-disparagement wording.