Any incident that happens in office, needs to in writing and not oral complain. So, get it writing from the lady on the Manager X. If she gives in writing then call talk to the her Manager and clarify on the complain. Once as an HR you are convinced, form a committee which is headed by a Senior Lady employee of the company who can conduct the enquiry and ask them to submit a report to the Management. Based on the committee report's HR can let the company decide to proceed further.

If the lady employee is not willing to give it in writing then you can ask her to give that no alligation exist on him & close the enquiry.

Incident that happens at work and at home, need to be treated sepertely and cannot be brought to work.

Regards