"Two best friends murdered... and forensic evidence left behind... he was very sloppy. A crime of passion. I guess he didn't watch much CSI on tv. ;)"
What forensic evidence was left behind? The only person who really knew anything about Doug was the best friend... and she was killed. All that was left was a dead body and a smashed up stereo. He took out all the cameras and listening devices.
:)
"If you mess with the King's Queens, you better watch your Ace, Jack."
And sure, MAYBE blood (from getting hit in the face) and MAYBE hair follicles...
but where would the police start? Again, noone really knew about Doug's existence other then the best friend. The first suspect would be Matt, if anyone. Then it's a dead end.
"If you mess with the King's Queens, you better watch your Ace, Jack."
I really don't want to get into hypotheticals but its the only way i can respond to your post. Anyway as long as Doug keeps killing he'll eventually be caught considering how bad he performed Amy's murder. Trends count. Especially DNA trends.
What about the phone calls? The coffee barrista seeing them talk? He would definitely get caught. The last scene with him doing it again months later was the only unrealistic part