Elementary, dear Watson!

I love RPG and I love murder mysteries. When I am not blogging, gaming or drinking coffee, I am probably listening to a Sherlock Holmes audiobook or watch the latest CSI episode.
I always wanted to have a great murder mystery adventure perhaps as part of another campaign or as a whole campaign. I still remember the good old times, when I was still in high school, when I discovered the roleplaying game “Private Eye” on a friends’ bookshelf. As far as I can remember we never actually played it, but I found the idea to play a private investigator in a roleplaying game written for murder mysteries and the like intriguing.
When I run or play Call of Cthulhu we normally have a lot of opportunities for criminalistic activities. We hunt for clues, talk to suspects, do research in libraries, so it’s the closest thing I have experienced to a detective roleplaying game.
When d20 Modern came out a few years ago I made some plans for a campaign with psychic investigators like in the Agents of PSI minisetting that never came out of the planning stage. My main problem always was, how do I create a compelling murder mystery without working everything out to the miniscule details and without resorting to a lot of Search and Research tests? And how do you handle psychic abilities in a murder mystery? I haven’t found an answer to these questions yet, so I ask my readers to share their thoughts.