At first to La Touche this seemed the end of the case. This man’s evidence definitely proved Felix innocent. His next business would be to examine Boirac’s hand, and, if the mark was there, the matter was at an end. But as he thought over it he saw that this was indeed far from being the fact. There was still the alibi. As long as that stood, a clever counsel would insist on Boirac’s innocence. To a jury the thing would be conclusive. And this ex-policeman’s evidence could be discredited. In fact, the very thing that had enabled them to get hold of it--the man’s dislike of the official force--would minimise its value. It would be argued that Hill had invented the scar to upset the police case. By itself, a jury might not accept this suggestion, but the alibi would give it weight, in fact, would make it the only acceptable theory. However, the next step was clear. La Touche must see Boirac’s hand, and, if there was a scar, Hill must see it, too. About eleven o’clock therefore, the detective hailed a taxi with an intelligent looking driver. Having reached the end of the rue Championnet he dismounted, explaining to the man what he wanted him to do. A few moments later found him once more seated in the window of the café, his eyes fixed on the Pump Construction office across the street. The taxi in accordance with orders, drove slowly about, ready to pick him up if required. About quarter to twelve, Boirac came out and began walking slowly citywards. La Touche quietly followed, keeping at the other side of the street, the taxi hovering close behind. Then the detective congratulated himself on his foresight, for, on Boirac’s reaching the end of the street, he hailed another taxi, and, getting in, was driven rapidly off. It was the work of a couple of seconds for La Touche to leap into his car and to instruct his driver to follow the other vehicle. The chase led down to the Grands Boulevards to Bellini’s in the Avenue de l’Opera. Here Boirac entered, followed by his shadower. The great restaurant was about three parts full, and La Touche from the door was able to see Boirac taking his seat in one of the windows. The detective dropped into a place close to the cash desk, and, ordering table-d’hôte lunch, insisted on getting the bill at once, on the grounds that his time was limited and that he might have to leave before finishing. Then he ate a leisurely lunch, keeping an eye on the manufacturer. That gentleman was in no hurry, and La Touche had spent a long time over his coffee before the other made a move. A number of people were leaving the restaurant and there was a very short queue at the cash desk. La Touche so arranged his departure that he was immediately behind Boirac in this queue. As the manufacturer put down his money La Touche saw his finger. The scar was there! ‘Here at last is certainty,’ thought the detective, as he drew back out of the other’s sight. ‘So Boirac is the man after all! My work is done!’