Byomkesh crossed the road rapidly and approached the gate. He looked around, but in the dimly lit environs of the lake, no one was visible.

Byomkesh hovered for a while at the gate before walking through it and proceeding towards the lake’s shore. He had barely taken a few steps when a man detached himself from the shadows under a tree and beckoned to Byomkesh. When the latter approached him, the man suggested, ‘Come, let’s go and sit on that bench there.’

The bench was located under a tree by the water’s edge. Byomkesh sat on the right end of the bench. In the dull glimmer of faraway lights their faces were indistinct at best. Byomkesh said, ‘Now tell me what you know.’

‘I will,’ the man assured him. ‘Actually, the person I wish to talk about is very dear to my heart. That’s why I’m feeling a bit awkward. Have you a cigarette on you?’

Byomkesh took out his pack of cigarettes and offered it to the man. The latter took one and returned the pack to Byomkesh. Then, as he reached into his pocket, as though rummaging for matches, he suddenly said, ‘Look who’s approaching.’ His gaze had moved past Byomkesh and travelled beyond, as if trained on someone approaching from behind the spot where Byomkesh was seated.

Byomkesh turned back to look and waited. He was prepared for the pressure he felt on his back, below the left shoulder. Then he whipped around. His companion had been trying to thrust a porcupine quill into his back. For a second, the man sat there, bewildered. Then he tried to get up and run. But Byomkesh’s iron fist had landed on his jaw like a heavy-duty weapon and laid him out, face down.

In the meantime, two other men had appeared, as if out of thin air, like Aladdin’s genie. They seized the prostrate man by his arms and hauled him to his feet. Rakhalbabu wrenched the porcupine quill out of his hand and announced, ‘Probal Gupta, you murdered three men in cold blood and attempted to murder two others. We’re taking you to the police station.’

A fortnight later, on an overcast morning, an informal tea session was taking place at Byomkesh’s house. Ajit was present and so was Satyaboti. It had been raining almost incessantly since the previous night. The rain would barely stop before starting again. The wrath of summer seemed to be abating, transformed by the rain into rivulets of love.

‘So,’ Ajit observed, ‘you sent such a wonderful singer to jail! The man is, indeed, a truly gifted singer. Did he really kill all those people?’

Satyaboti said, ‘The man was surely deranged.’

‘Probal Gupta isn’t deranged,’ Byomkesh told them. ‘But neither is he entirely normal. He came from an affluent family and the vagaries of fate had, without warning, reduced him to a state of penury. His plight had soured him. Of the seven deadly sins, two were intrinsic to his nature: Greed and envy. Compounded by his dire financial situation, these two failings were instrumental in unhinging him.’

Satyaboti pleaded, ‘Tell us everything from the very beginning. How did you deduce that Probal Gupta was the culprit?’

Byomkesh poured himself a second cup of tea and lit a cigarette. He exhaled slowly and began to speak in a leisurely manner. ‘The keyword in this tale is “porcupine quill”.

‘Had the killer been demented, our hands would be tied, for the application of logic alone would never have led us to him. But if he were not insane, then the question arose about his reasons for using porcupine quills instead of knives and daggers. There had to be a motive. What could it be?

‘Every time the assailant chose to leave the porcupine quill in the victim’s body, it was clear that he wished to create the impression that all the killings had been committed by the same man. The message conveyed was: He who had killed the beggar, had also killed the labourer and the shopkeeper. But why?

‘To me there was just one answer. Starting from the beggar to the shopkeeper, none of the three was the killer’s actual target. It had to be someone else. He had committed three random murders just to confuse the police so that they would be unable to pin down a motive.

‘Then the same attempt was made on Debashish. By a stroke of luck, he had a narrow escape. But the identity of the killer remained unknown.

‘My search for Truth began at this point. It had still not been proved beyond the shadow of a doubt that Debashish was the killer’s actual target, but one could assume that there would be no more victims after the attempt on his life. From the beggar to the industrialist—it would be normal to expect the trajectory of murders to end there. Anyway, the situation certainly deserved an investigation.

‘The investigation revealed that Debashish was not particularly close to anyone other than the men who went to Nripati’s evening tea sessions. His employees at the factory were very fond of him and not even a day’s strike had ever been called by the workers there. Yet another fact had surfaced: Before her marriage, Dipa had fallen in love with someone and tried to elope with him. But the attempt had been foiled. Dipa had married Debashish soon after.

‘No one but Dipa was aware of the identity of her secret lover. Who could it be? Dipa’s family was staunchly conservative in its ways and she was not allowed to socialize with men who weren’t known to them. But when her brother’s friends dropped in for a visit, she was allowed to meet them. Her boyfriend was therefore likely to be one of her brother’s friends—either Nripati or one of the young men who frequented his place.

‘This assumption also offered a clue about a possible motive. If Dipa’s secret lover was a really vile person and devoid