Unless we’re very lucky, most of us at some point have to deal with that most unpleasant and awkward of situations: the neighbor who turns out to be a former Nazi. It can be disconcerting to learn that the kindly old gentleman who always smiled at you on the sidewalk once oversaw the brutal degradation and murder of thousands of people. This knowledge can cause stress and interfere with your enjoyment of home life and with your productivity at work.

But with a little planning and common sense—along with help and support from friends—you can meet the problem head-on and prevent this predicament from further disrupting your life. Just follow these basic guidelines:

Set up a meeting with the ex-Nazi neighbor. You do not need to tell the ex-Nazi what the meeting is about; simply ask him when would be a convenient time for you to stop by for a few minutes. Don’t schedule the meeting too late at night, as the ex-Nazi will be old and probably has an early bedtime. Also, consult the History Channel listings to ensure you do not interrupt a night of nostalgia for the ex-Nazi, making him less likely to be conciliatory.

Enlist the help of other (non-Nazi) neighbors. Share your concerns with other neighbors and ask them if they will stand with you in your intervention with the ex-Nazi. You will be much more persuasive if you can demonstrate that many people disapprove of his past behavior.

Gather and organize documentation. The ex-Nazi neighbor is less likely to put up a fight if you can confront him with evidence of his misdeeds, so do your best to compile photographs, signed orders, and oral testimony. This record of his actions will drive home to the ex-Nazi that you are not simply ganging up on him like a bunch of sorority girls.

Go as a group to the ex-Nazi neighbor’s house at the appointed time. When he sees the crowd of people, the ex-Nazi may not want to invite you in. Be prepared to use force to push back the door, but take care not to cause harm to the ex-Nazi while entering his house. It is best to file into his living room and stand as a group. One neighbor should guard the door to the basement steps so the ex-Nazi does not impulsively rush to his bunker.

Take charge of the meeting. State your concerns about his behavior in an assertive tone. Remind him that he hurt many human beings and that this behavior will not be tolerated. Avoid using labels, but point out that he caused pain and discomfort to a large number of people. Above all, remain calm but firm. The ex-Nazi neighbor may try to bait you by bringing up Dresden or muttering German curses, but getting emotional will only make the situation worse for everyone.

Present a united front. You and your non-Nazi neighbors may have your differences about lawn maintenance or barking dogs, but you should make clear to the ex-Nazi that you all agree his past behavior is unacceptable and that he needs to leave the neighborhood. The ex-Nazi may try to create a diversion by scapegoating a segment of your group, but do not buy into his arguments, even if they begin to sound reasonable. Calmly bring the discussion back to the issue at hand.

Force the ex-Nazi to agree to a move-out date. Explain to the ex-Nazi neighbor that after he is relocated, you will be taking possession of his house and belongings and that surely he can understand the precedent for this.

Get the agreement in writing. Immediately after the meeting, send a letter to the ex-Nazi thanking him for his time and laying out your understanding of what was decided. As a courtesy, you may want to send follow-up letters as the move-out date approaches.

Send thank-you notes to the non-Nazi neighbors who participated. It is imperative that your non-Nazi neighbors know you appreciate their help with the intervention in case a similar situation arises in the future. You all need to keep an eye out for further threats to your block. Come to think of it, wasn’t it a bit odd last year at the Christmas party when kindly old Mr. “Jenkins” from “New York” couldn’t tell you which team Lou Gehrig played for?