Later that day, after the police had arrested the hapless Terry Dactill, Sherlock Holmes elaborated on his chain of reasoning.
"This morning, when Penny Traitor gave Dactill the cassette of 'Lord of the Rungs' to load into the Spectrum, he made no attempt to switch it on. His first reaction was to rewind the tape. That was inconsistent with his account of the events of the previous evening, in which he stated that he had rewound the cassette before handing it to Mel Bourne and had then unplugged the equipment. It was clear that he was lying."
"The all-important clue, however, was the hi-score chart displayed at the end of the game. The scores themselves were irrelevant, but the surprising fact was that the scores were there at all, as they could not have been an integral part of the original program and would have been lost when the computer was switched off after play." "It follows that the cassette which was found in the rifled desk drawer was not the original but a copy which had been SAVEd from the Spectrum after the game had been played."
"Let us now imagine the probable sequence of events. Dactill had been approached by Moriarty Micros and paid to steal the game. He assumed that Bourne would lock the cassette in the safe as usual, and the only way he could steal the game was to SAVE it from the computer itself. While the others chatted in Bourne's office Dactill pretended to unplug the equipment, planning to return later."
"He did so that night and immediately SAVEd the game. He then went to Bourne's office and set about faking a break-in. His plan was to create the impression that an unknown agent had forced an entry to the building, ransacked the office, opened the safe and copied the master cassette, finally replacing it in the safe before leaving."
"If suspicion should fall on Mel Bourne, as the only person who knew the combination of the safe, or, indeed, a professional safe-cracker, then all well and good."
"His first mistake, however, was to smash the window from the inside, scattering glass outside on the fire escape. That indicated an inside job, and eliminated Miss Traitor and Horace Goezski as neither had keys." "To provide further evidence of a burglary Dactill then forced open the desk drawer and found, to his surprise, the master cassette, which he had believed to be in the safe."
"It was then that he made his second error of judgement. He exchanged the cassette for the copy he had made, knowing the quality of the original recording to be superior. He assumed that no-one would notice the substitution, forgetting that the copy would contain the hi-score chart."
"He then left the building, neglecting in his haste to switch off the computer, which explains why it was so hot when I picked it up. Dactill had to rewind the cassette this morning because, as he knew only too well, it was the copied version and not the master cassette. Simple, eh Watson?"