Singh continued. “If we let the software keep tracing their movements from the previous day, week, month, or year, we can collect all sorts of interesting data. Every time they enter a building we can determine who they are meeting with. Then we can trace the movements of those new targets as well. In this way, we can reconstruct entire networks of people, establish relationships, property locations, patterns of movement, et cetera, and all in far less time and for far less cost than traditional methods.”

Jack ran the calculations in his head, multiplying the number of policemen times the number of hours in stakeouts, surveillance ops, shift rotations, vehicle miles driven, and a dozen other cost factors that added up to hundreds of thousands of dollars in salaries and expenses for even small intelligence operations over a decent length of time.

“Let me show you a quick example. We’ve been running this test program for the last sixty-four days. So let’s see what Mr. Ho has been up to.”

Singh tapped several more keys. First, he cleared the screen of the yellow line representing the other delivery driver, then extended the time-trace parameter to sixty-four days. Nearly instantly, the screen filled with a crazy spiderweb of red lines, all tracing Ho’s movements, and all centered on Ho’s residence. The red lines mostly tracked along the same routes, with a few loose strands snaking around the island to parks, recreation areas, and shopping centers.

“Now, if I hit another key, the software will show me Mr. Ho’s five most visited locations as measured by length of stay.” Singh executed the new function, isolating five specific locations, and took away all of the red spiderweb trace lines to clarify the image.

“As you can see, two of those five locations are his home and his place of work. A third looks to be a local bar, and the fourth a horse-racing venue. The fifth . . .”

Singh tapped more keys. “Is the residence of this woman.” A photo popped up, along with her personal stats. It was a thirty-two-year-old single woman, plain and somewhat heavyset.

“So Mr. Ho spends quite a bit of time with this woman. For the sake of her privacy, I won’t pull up her name. But just for fun—”

“Dr. Singh—” Lian said, but too late.

Dozens of tracer lines, each in a different color, radiated out from the woman’s apartment. The home terminal of each line appeared, along with the images of their occupants—all men, of various ages and races.

“It seems Mr. Ho’s ‘friend’ has a lot of other friends.” Singh raised an eyebrow. “If you catch my meaning.”

“Friends who are friendly by the hour, judging by the time stamps,” Jack added.

“That’s enough, Dr. Singh.”

“Yes, ma’am.” Singh tapped another key and all of the data disappeared, leaving only the live overhead image of Singapore on the screen.