Had a look at the criminal complaint just to find out where the perpetrators had gone wrong.
Sending anonymous tweets and E-mails, they purchased pre-paid debit cards to send packages to their home, various harassment techniques such as ordering a pizza "pay on delivery" at 4:30 AM, and so on and so on... how on Earth did the NPD ever figure this out?
Turns out the perpetrators flew from California to Boston area (Natick) to put a GPS on the Steiners' car, which they couldn't do because it was kept in a locked garage, so they rented vehicles to surveil the Steiners, their license plates were noted and given to Natick Police Department (NPD), and the rental agency was contacted.
Once the eBay operatives were identified, they tried various misdirects and obfustication techniques, but NPD a) verified their statements, and so figured out they were lying, and b) contacted eBay directly, which had a security team respond in good faith, and the whole plan unravelled.
One, single mistake is all that stood between a long campaign of harassment and getting found out. One good local police department who took the trouble to look deeply into the problem and figure out the truth despite a torrent of misdirection and obfustication.
I wonder how many more campaigns of harassment are ongoing, led by people who know how to conduct vehicle-based surveillance, or encouraged by ineffective or lazy policing.