The police are allowed to lie. Without context it's hard to say but the statements you have described are the kinds of things police tell suspects to get them to confess or provide information.

Was the other county even in the same circuit? The solicitor is being pissy. He spoke in court based on assumptions and it bit him in the butt. If the detective said to him what you claim, he was a fool to tell the court wasn't going to pursue charges without talking to that county's solicitor first.