I seem to have a dilema. I can solve intermediate cases, no problem. But everytime I've tried to do a hard case I've either had to give up, or I accused the wrong person. People keep clamming up on me. Are there any tips for solving hard cases, or do I just need more practice?
I remember when I was new and couldn't rise a level when I thought I should be able to, it was because of the way I had chosen my skills. In order to prevent clamming or get them to open up once again when they have already clammed, you need to work on your interviewing skills for EITHER tough or charming, according to your character type. This means Sweet Talking and Rule Bending for charming or Interrogation and Intimidation for tough. Augmenting those skills with the corresponding makes a difference, of course.
I see you are in a very small agency, but even so the other agents may be able to ask more questions if you store the case and then ask them to open it, and tell them what information you need. They can also help you by using their contacts on your cases in the same manner.
But if you are simply not getting enough suspects, you'll just need to wait until your interviewing skills are improved.
And nice hat, by the way! ; )