Without knowing what the specific items of evidence in question are, I can let you know this:
If it's not protected information, ie. protected by privacy laws, then it's quite possible they may have showed it to your boss.
Another thing to take into consideration is relevance: is the alleged crime linked to your job in any way? You have to consider what would be the officers' motivation in showing detailed evidence to your boss. They're not going to do that unless it's directly related, or unless it's going to benefit their investigation in some way.
Again, I'm not sure what the alleged crime is, but if it's been a month and half and you have not been charged, then perhaps they don't have enough evidence to formally charge you, OR (and hopefully it's not this option) they could be gathering evidence in order to bring a grand jury together and attempt to have you indicted.
I hope that helps. A gentle reminder: please take a moment to rate me using 3 stars or more at this time, I don't receive a salary here, and even though I've answered your questions and concerns, I won't be compensated for my time unless you leave a positive rating. It's free of charge to rate me, and I'll answer any relevant follow up questions after you've left a positive rating. Thanks!