windows or doors. âWhat kind of car is that?â he asked an Underground security guard who was also watching it.
âItâs our new tunnel cleaning train,â the guard answered, raising his voice as the car passed by. âWeâre trying it out. It takes in about two million pounds of trash and garbage a day.â
âWhatâs the most unusual thing it ever picked up?â Joe asked.
âI never saw it myself, but I hear we got a mattress once,â the guard said, shrugging. âBut mostly, lots of umbrellas, cell phones, garbage, and clothing.â
Joe waited and watched the platform for a few more minutes, then decided to return to the flat. All the way back, he kept his senses alert, watching and listening for a sign that the intruder was still nearby.
â¢Â  â¢Â  â¢
While Joe was tracking the intruder, Frank and Jax checked out the flat. At first Frank felt a little woozy from his slamdunk to the bottom of the stairs. But he grew stronger with every step. Careful not to disturb any possible evidence, he led Jax through the living quarters and then into the medical suite.
When they got to Jaxâs medical lab, Frank stopped. âWhere do you keep your inventionâthe Molar Mike?â he asked.
âItâs in my medical office,â Jax answered.
Jax started toward the office. As Frank followed, he noticed something glimmering on the floor. âJust a minute,â he called out. He walked over and crouched near where heâd seen the glow. A piece of gray metal lay on the floor.
âItâs shaped like part of a leaf,â Jax observed, crouching down with Frank.
Frank reached for a tissue off the lab counter. Then he used it like a glove to turn the piece ofmetal over. âThereâs part of a hinge on one end,â he said. âIt might be half of a clasp. Have you ever seen this before?â
âNever,â Jax said.
âDo you have a camera in here?â Frank asked.
âSure,â Jax said. âItâs one of those instant ones.â He went to a closet, got the camera, and brought it over.
âPerfect,â Frank said. He took one shot of the front of the pewter fragment, and another of the back. Then he folded the tissue over the metal and slipped the package into an envelope.
While Frank took the pictures, Jax went into his office. âThe Molar Mikeâs still there,â he reported, quickly returning to the lab.
Frank heard the police car, and he and Jax went to the door. Joe arrived at the same time.
âYou okay?â Joe asked his brother. âWe took quite a roll out there.â
âI donât even remember it,â Frank said. âI got slammed from behind, and then I blacked out, I guess. What happened exactly? Someone was inside the flat?â
âUntil you started to open the door,â Joe said, nodding.
âRight,â Frank said. He thought back to the moment at the top of the steps. âNow I remember. I tried to turn the key, but it wouldnât budge.â
âThe person inside was probably jamming thelock,â Joe pointed out. âThen heâor sheâcame barreling out, knocked into you, Frank, and shoved you down the stairs into me. We both ended up on the ground. The intruder jumped over the stair railing and ran off. I took off after him but lost the personâs trail in the Underground.â
âCan you describe the person any better?â the policeman asked, introducing himself as Officer Somerset.
âWell, I didnât get a really good look,â Joe said. âI think it was a manâbut it could have been a woman, I guess. Pretty athletic. He dropped from the landing over the stairway, and took right off. Outran me for several blocks.â
âHow about clothing?â the officer prompted.
âDark pants and jacket, black cap with a little brim on the front . . . I couldnât see any