The owner of the laptop missed his opportunity to recover his property by trying to publicly shame the woman into returning it. That was a counterproductive waste of time. She could just claim she bought it from someone, and how could he, or the police, prove otherwise?
Anti-theft software should be designed to allow the thief to use the laptop on a guest account, while password protecting your personal account. You want the thief to use the laptop. Locking it remotely will only ensure that it is immediately disposed of, or sold for parts.
So, assume your laptop is stolen and you've activated the remote tracking software: immediately call the police and file a report. The police won't do a thing unless you take that first step. Next, start collecting data on the thief: home address, work/school address, phone numbers, images of the thief using it, etc. Organize all of that data into a folder and take it, along with a copy of your police report, to the local police station. Show them that you know exactly who has the laptop, that person's address, the location of the laptop, etc. Also point out that if this person was the thief, there is an excellent chance that additional stolen property will be found at their residence.
The police now have the justification they need to go knock on that person's door, or possibly get a search warrant. Granted, the person who has it may still claim it was purchased from some third party, but when police are standing in someone's home, showing them pictures of their own faces taken through the laptop camera, and saying, "Give us the laptop now, or we'll come back with a search warrant", the chances are excellent that it will be handed over.
No one may be prosecuted, but you'll at least have your property back. Of course, this scenario presumes that the police care enough to follow through with the information you provide. In larger cities, they may not bother, but in smaller towns and rural areas, they may be very happy to assist when you present all the evidence they need on a silver platter.