Credit: iStockphoto/procurator

"Keep your eyes on the camera!"

The woman jerked her back up. Her eyes were glazed, impenetrable now.

"I'll ask you again," the soldier whispered. "Are you just here to visit the temple? Yes or no."

"Yes." The zygomatic major twitched again. More pronounced this time. She was lying.

The soldier peered at his clipboard, waiting for my judgement. He smiled when it came. "That's all my questions. You have been denied access to the State on the grounds--"

"No!"

"--on the grounds of suspicion of entering the country on false pretences. You're free to leave." He marched to the door and swept it open. Loud chatter came through, then cut to silence. Everyone who waited always took a keen interest in the outcomes. Would she come out and turn left towards the customs officials or right and back the way she came?

"Please. I must be allowed in."

"Put on your veil and get out." The soldier gripped the handle of the door, impatient.

The woman stared dead ahead at the camera. Dead ahead at me. Lowered brows, narrowed eyelids, lips pressed together. Anger. Then: raised inner eyebrows, raised cheeks, lowered corners of lips. Anguish. "My fiance died on your streets." Her head dropped. "I must see the place he fell. Please."

The soldier didn't tell her to lift her head this time. His lips puckered slightly, incisivii labii superioris and incisivii labii inferioris muscles tensing. A sign of compassion.

He closed the door.

Facial-recognition software was first successfully introduced in The Netherlands, in a collaboration between the Dutch government and Philips Technology. Traditional methods of identification, in addition to other emerging technologies such as retinal scanners or digital fingerprinting, were found to be prohibitively expensive to implement, or susceptible to fraud.

Following this, a Japanese-led consortium developed the world's first microexpression-recognition software. The main customer was the U.S. Dept. of Defence, who used the system to help interrogate terror suspects in accordance with the Geneva Conventions.

"What was his name?" The soldier pulled a tatty photo from his breast pocket. He gazed at the picture. His orbicularis oculi, pars orbitalis, and zygomatic major contracted indicating happiness. The muscles shifted. His frontalis, pars medilis, frontalis, pars lateralis, and depressor supercilli tensed, betraying fear.

"Irfan." A slow teardrop ran down her face and dropped onto her dress. She trembled.

The solider fumbled around the other side of the desk and then stepped up behind the woman. "Here," he said, offering a tissue.

She took it and dabbed her eyes. "Thank you."

"You're welcome." He looked awkwardly from the box of tissues to the door. "I'm sorry for your loss. Let's just clear his details and then you can go through." He went back to his desk, sat down, and began writing on the clipboard.

"So, his full name."

"Irfan--" The woman hesitated, considered lying again. "Irfan Siddiq." This time she told the truth.

The soldier didn't need my analysis to know that. He recognised the name straight away. His light-pen dropped from his fingers, clattering against the screen.

"Irfan Siddiq who was killed on December 20 in the Old Market?"

His face stilled, waiting for her answer.

Analysing the thousands of microexpressions a typical detainee made during the course of a long, rigorous interrogation period was a painstaking task for a team of specialists.

The new system, codenamed Diogenes after the Greek philosopher of antiquity who wandered around Athens with a lantern, peering into people's faces as he searched for an honest man, was later sold around the world.