A global kidnapping case that began in Chicago’s tony Lincoln Park neighborhood and spiderwebbed through the suburbs to California, Mexico and finally Beijing, is the latest example of a surge in digital strongarm thefts.

For the past year, NBC Chicago’s investigative team has been unpeeling cases that could be described as “Grand Theft: Crypto,” kidnappings for ransom paid in digital currency, many times featuring Chinese organized crime groups.

When a band of Chinese nationals showed up at a home in Lincoln Park, they weren’t selling something. They were there to take it, grabbing a whole family, including an infant and the babysitter, for ransom totaling $15 million in crypto currency.  

The hit squad was…