No expert would recognize the VW as a means of transport reserved for officers of the criminal investigation department. Its radio set was hidden under the dashboard and the antenna was a mere twig, slightly rusty. No one would suspect that the back seat contained a well-oiled carbine, neatly wrapped in canvas, and complete with six magazines, or that the harmless nose of the car was filled with a complete collection of utensils that police officers think they need during the lawful exercise of their duties and including such items as a small suitcase full of burglar's tools, a powerful searchlight, a dredge, gas masks and a tape recorder.

But nothing was suspected and the officers looked as innocent as their vehicle. Grijpstra is a fat man, and de Gier neither thin nor fat, qualities they share with a large number of other men in Holland's capital. Grijpstra wore a badly fitting suit made of expensive English striped material, with a white shirt and a dark blue tie, and de Gier a made-to-order suit of blue denim, a blue shirt and a many-colored scarf neatly folded around his Adam's apple. Grijpstra's hair looked like a well-worn scrubbing brush and de Gier's curls were beautifully cut by a proud and highly trained coiffeur taking an almost personal interest in the glamor of his clients. De Gier's curls were so well shaped, in fact, that he could be mistaken for a woman, if viewed from the rear, and only his narrow hips protected him from attacks from that side.

A pedestrian, in a hurry to reach his parked car, bumped into Grijpstra and hurt himself against the large model service pistol that the adjutant carried under his jacket.

"Watch where you're going," the pedestrian mumbled ferociously.

"Yes sir," said Grijpstra kindly.

An ordinary car was parked on the sidewalk and two ordinary men ran through the rain until they reached the porch of number 5 and tried to catch their breath.