Red and blue capsule with grey strip?

I don't think so. It was in one of my old perscribtion bottles without a label.

Could it have gotten there accidentally? It fits your description closely except there is a small "L" in the blue part and a "5" in the red part. Could these marks have faded? I've searched through 100's of pills on multiple sites and this is the only match with a grey band in addition to the blue and red on the capsule ends. The red and blue are very strong colors. Do you have anything to add to the description?

The blue and red parts are more glossy like coating. The grey strip Is a little bit rougher but still smooth. if you break it in half its white. Is there any way I can test and see if it's acetaminophen?

No. But you could take it to your pharmacist and ask him/her to identify it. This is their specialty.