I've found it best when forced to deal with such people to keep my distance. But when that's impossible, I to try to only speak with them when there is one other trustworthy person present. That way, there is a witness to possible later lies.
From the article:
Some individuals have developed skill in lying to others and have no fear or regret in engaged in lying to a Judge, police officer, therapist, psychiatrist, family member, spouse, supervisor, etc. They can also present as very calm or charming, provide appropriate eye contact, maintain norming breathing rhythms, be personable or friendly, and have calm body language. These individuals certainly fit the description of a sociopath and can be very dangerous for society and the lives of those who are in relation to them in some form or fashion.I have learned that such persons, while rare, can be found in almost any institution, including the Church. They elude responsibility for bad actions or inaction, while portraying themselves as open, caring people. They're experts at deflecting responsibility for their actions, even when they bear clear responsibility for them. This can make their lies all the more damaging, because of the credibility credulous people may assign to charming liars who misuse others' goodwill.
Private confrontation, if bringing unsuccessful resolution to the lying pattern, should be followed by confrontation with a third and objective individual witness present. And if that confrontation is unsuccessful, it should be followed by confrontation in the presence of the affected group. All of this is designed to get the pathological liar or pathologically irresponsible person to a place of accountability and to gain a healed, recovering relationship with others. It is precisely the strategy for conflict resolution Christ gives to His Church in Matthew 18:15-20.
If failure to bring acknowledgment or a desire to change on the part of the pathological liar happens, more drastic action will be needed.
Pathological lying threatens any group--from the family to the congregation, from friendship to the nation--threatens any institution in which it happens.