It wasn’t high quality by any stretch, but the video showed enough for Andy to realize he was seeing something that no one in the local police had admitted. These were clearly wounded D.C. Metro officers, three of them being helped out of the elevator and placed into a pair of cruisers. All three men bled from their faces, and two of them were all but dragged by their colleagues. Just as they finished loading them, the elevator door opened again, and another cop staggered out and fell into the arms of his colleagues. This man looked as if he was bleeding profusely from multiple gunshot wounds. He was placed inside one of the cruisers himself, and the cars rolled off, east on Q Street NW.

Right before the video ended, the squad cars rolled right by the woman holding the cellphone that made the recording.

When it was over, Andy looked up from the phone at the Chinese sandwich artist.

“Did you show this to the police?”

She shook her head and looked down. Andy had met enough foreigners in the District to read the signals. She didn’t have papers to work legally here, so she kept her contact with authorities to a minimum.

He stopped the video and pushed it back a few seconds, then let it play again. The woman offered to sell him the entire phone for $500, but he declined, gave her a hundred bucks for her time, and e-mailed the video directly from her phone to his Washington Post e-mail account.

A minute later he was seated at a table in the restaurant, and the Chinese lady was looking at him like she thought he might try to steal her cell phone. Instead he pulled out his own phone and called a buddy in the D.C. Metro Motor Pool, an old cop who used to work out in District Seven but was rewarded with a cushy desk job for the last few years before retirement.

“What can I do for you, Andy?”

“I’m trying to find some cops, but I don’t know their names, only the numbers of their squad cars. If I give you the numbers, can you tell me who drove them on a particular shift?”

“I could tell you what police district they were assigned to and what PSA—that’s police service area. You could call somebody at that PSA and get more info. Who was behind the wheel depends on who was assigned to what unit that day. Bunch of variables.”

Andy read the number on the first cruiser to the sergeant. As soon as he finished the sergeant said, “Nah, you’re one number short.”

“No, that’s it. That’s the entire number on the cruiser.”

“Sorry, Andy. We haven’t used that number since . . . well, let me look it up. Since nineteen ninety-seven.”

Andy quickly read off the next number. It was six digits long.