Editor's Note: Chen Yingliang, 30, is a police officer from Anhui province who was responsible for downloading and analyzing data for Operation Angel.

At first, the prospect of downloading 4 trillion bytes of obscene child images from the Web and handing in an analysis report within a month seemed an impossible task.

Such a large quantity of data would ordinarily take about 50 days to download, let alone the time it would take to analyze.