Go to the lawyers about a problem with an individual and you'll probably find that they will advise you to do little or nothing. Why? Because more problems are generated by commission than by omission and in most cases if you want to avoid complications you will sit tight.
Of course, they don't have to work alongside your problem.
That's why a key line in dealing with lawyers - or HR types, for that matter - is "We cannot tolerate this." You then have to be prepared to back that up with supporting evidence, general and specific. The line is important because they may assume that you can tolerate it. In fact, you've probably been tolerating it for some time and only approached the dismal duo of Law and HR after exhausting your patience or depleting your supervisory bag of tricks. Can you blame them for thinking that they may be looking at two problems: the one you brought in and the one that is you?
As a result, part of your strategy must be to convince them that you are not a problem reporting a problem. You must impress them with your professionalism and your reasonableness. Your demeanor should cause a little cartoon bubble to float above your head and that bubble should read "Good witness." If you appear to be disorganized, vindictive, uncertain or prejudiced, other bubbles will appear.
This is especially challenging because, due to the procrastination that you must vow never to repeat, your mood may not be the best. Restrain yourself. Understate your case. And zero in on the solid proof that reasonable action must be taken.
If you need more proof, bear-hug the lawyer and HR. Bring them into the process so their fingerprints are all over your plan of impending action. This will increase the likelihood of their support in the future. As was once said, people seldom argue against their own data. You want your strategy to become their strategy.