‘How can you have ruled out the possibility of some street mugging?’ Li questioned again, apparently anxious to assert his number one position in the bureau, though with little knowledge about real police investigations.

‘Well, she was far from a well-to-do one. Nor dressed like one. If anything, she looked more like a poor rustic “country auntie”. She had to do all the dirty work for the patients there, as you can imagine.’ Qin put a picture on the table. ‘So we could pretty much rule out the possibility of any chance mugging for money.’

So far it had been going on like an exclusive discussion between Qin and Li. Yu looked at Chen, who seemed to be quite content with the role of patient listener, wearing an unfathomable look on his face.

‘She lived in that area?’ Li asked again.

‘No, in the Minghang area. She had to take the bus, and then the subway to Minghang, but to save a few pennies she chose to walk to the subway station on Nanjing Road, I think.’ Qin went on after a short pause, ‘And there may be another possibility for that. She did hourly jobs for several families as cleaner, cooker or nanny during the day. So she could have been on the way to one of the families.’

‘What else did you find?’

‘Initially, we did not take it as a serial murder case, though we did notice something unusual about the timing and the location, as I’ve mentioned. Then the second victim turned up about a week later. A weather anchorman named Linghu at the weather bureau, in the city government building.’

‘In the city government building at the People’s Square,’ Li echoed mechanically. ‘What do you think, Chief Inspector Chen?’

‘Me? I’ve hardly learned anything about the case – not until this morning,’ Chen said. ‘Please move on, Detective Qin.’

‘Go on, Detective Qin,’ Li said, nodding.

‘We were talking about Linghu. According to one of his colleagues, Linghu had stayed overnight in the office, studying the formation of a sandstorm from the north with its potential impact on Shanghai. But according to another, Linghu stayed there for an international phone call to his friend in the States. It’s free in the office.

‘Whatever the reason, Linghu left the building at five thirty that morning, as recorded by the surveillance camera there. Around five forty, his body was found at the west end of the square, close to the subway station entrance. It’s walking distance – four or five minutes – from the office building.’

‘An even more central location, with several entrances to the subway station,’ Li commented again for emphasis.

‘Yes, the criminal has to be one capable of striking out with lightning speed. Like before, a single fatal blow, and the murderer disappeared into thin air—’

‘Not that thin air, I’m afraid; quite murky with the morning smog of late,’ Yu could not help cutting in for the first time. ‘That’s one of the reasons, I guess, why it was not witnessed by others.’