Solution to Part 3 (I seemed to have hit the post limit of GOG's forum).
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You are to take the encrypted text and run it through a series of Vigniere encryptions using different passphrases based on the hint.
First, it's about their work load. - "Liar and Thief"
Then, the whore secretary's abode. - "Kingstone"
Where do the wenches hide, each with her lover? - "NV"
Lastly, what is her name and then the other? - "Linda" and then "Melody"
You should get this answer:
TINYURL_k9zg5yb
It will lead you to this story segment:
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You manage to find the address amidst all the garbled text of this sick killer. With the police behind you, you storm into the lonely abode, but only to find nothing inside. You realize then that it had long been abandoned. Before you was a computer and there was only a message to you.
“You’re very good at playing... but you’ll never find me. Can you guess where I am? You’re always one step behind! Till next time, my dear inspector!”
[url=http://41°13′41″N 115°3′22″W]END TRANSMISSION[/url]
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The killer did not anticipate that the computer had left coordinates of his whereabouts. Run it through a search and you'd get Metropolis, NV... a ghost town but blakstar's answer suffices being much more thorough.
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For those curious:
Throughout the puzzle, there are long alphanumeric text that are MD5 hashes. The idea behind it was that once you thought you had the TinyURL built correctly, you'd run it through an MD5 to see if you got the right TinyURL.
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CONCLUSION:
Keeping a low profile, you enter the abandoned town in the dusty Nevada desert, leaving the police afar to draw less attention. With the coordinates in hand, you tap the buttons on your GPS device, narrowing down the signal to its source. Several paces from you was a runned down hut. Everything you checked pointed to this place. This was it. He had finally slipped.
Carefully pulling out your Beretta, you silently sneak towards the frail wooden door. From inside, you could hear activity, no doubt the killer had figured he had cleaned all his traces. He had gone sloppy though and now it was payback.
In one smooth motion, you kick the door down and aim your gun squarely at a man with a cat mask on. The scent of blood was thick in the air, a troubling sign of how demented this bastard was. “FREEZE!”, you shout at the top of your voice. It was enough. It was all over.
The cat masked man simply raised his hands, yielding to you and the police that swiftly filed into his abode. “You got me!”, the man spoke, seemingly impressed that he had been beaten at his own game. “Will a few Steam keys earn my freedom?”, he offered.
“No, sick bastard!”, you retort. “I’ll take the keys AND jail you!”
It was all a game to the mad killer, Novotnus. But sooner or later, they all get sloppy. Now, it was all over.