[ossiblue]

I agree with those who suggest you call the police. Your concern is two fold. First, it looks like you're being set up for some type of traffic incident and the police should be made aware of what happened and be informed that you have an eye-witness to back your story. Second, you travel that route every day and you are concerned that whatever is motivating this person will be repeated or escalated and that you fear for your safety as well as his (be magnanimous.) To me, anything as bizarre as you describe, especially with him following you to work and taking pictures, warrants notification of the authorities just to get your position on record.