A suspected robber who police believe was behind a six-month crime spree that involved more than 50 store robberies in Beijing and Hebei province has been detained and brought back to the city, Fengtai police said.

Most of the victims were single female store owners and clerks who were in their businesses alone.

The suspect, surnamed Liu, was described by several of his victims as a "chatty customer" who started out pretending to be a friendly shopper before pulling out a knife to rob his victims.