The museum’s little silver bird is gone. Outside the service entrance, a muddy trail seems to point Puz and Curator Ada towards an ordinary blue car. There is just one problem: the car has not left its garage.
Before the doors opened
A night guard had checked the silver bird in its display at 3 a.m. When Ada arrived at 6 a.m., its place was empty. The side entrance had been forced open. The antique was small enough to carry, and valuable enough to tempt a thief.
Rain had stopped shortly before the night guard’s check. A clear set of car tire tracks crossed the damp gravel outside the service entrance. Puz asked the police to photograph them before anyone disturbed the ground.
The trail led towards a nearby underground garage. There, an examiner found matching tread patterns and distinctive worn patches on the tires of a blue car. It belonged to Professor Linden, who lived above the garage.
A car that stayed home
“I’ve been at home writing my book,” the professor explained. “I haven’t used the car for ten days.” The night attendant confirmed that the blue car had remained in its bay. The entrance camera showed every vehicle coming and going that night; the blue car was not among them.
Puz studied the examiner’s photographs. The tracks matched the blue car’s tires, yet the blue car had never passed the garage entrance. Ada looked from the photographs to the parked car. “How can both things be true?”
Two long visits
The attendant remembered something else. Mr Vale, who owned a red car a few bays away, had entered on foot at 2 a.m. He did not drive out until about 2:50 a.m. He returned in the red car at 5:10 a.m., then stayed until almost 6 a.m. before leaving on foot.
“People have their own parking bays,” the attendant said. “Collecting a car or parking it normally takes a few minutes. He spent nearly fifty minutes here each time.” There had been no queue or blocked exit.
A mechanic assisting the police checked both vehicles. They were the same model.
Marks beneath the cars
The examiner also found fresh marks at the lifting points underneath both cars. They were the sort made by a car jack, a tool for lifting part of a car. Each group included the same small crescent-shaped dent, as though the same damaged jack pad had pressed there. Neither owner had reported recent servicing.
Puz went over the times once more, then looked at the two cars. “The red car was used in the theft,” Puz said. “Now I know how those prints got there.”
How did the red car leave tracks matching the blue car’s tires?