Should I document the sexual harassment my colleague is experiencing?

The conduct of the offending individual should be reported to Human Resources along with the names of persons who witnessed the event. It is always a very good idea to document dates, times, and specific facts about events that violate the law or company policies. For your own protection keep the information somewhere other than at work or on company technology. If you are disciplined or terminated by your employer in retaliation for raising issues the information will disappear if on company equipment or on their facilities. It is also always a good idea to report misconduct to others and have them document the date and time that you told them, you can accomplish them by speaking with them about the details and then follow the conversation up with an email that says, "Thank you for talking to me today about ... Your willingness to listen and support me in this matter means a lot to me." In this way you will have an electronic document that has a date and time stamp that proves when you told someone else about the events. This will strengthen your position down the road if problems occur. You should seek the advice of an attorney who deals with employment matters if this situation continues or if you would like additional help. You will need to share more specific details to get more valuable advice.