I saw this movie about 15 years ago, I’m pretty sure while watching the Lifetime channel with my Grandmother. It might not have been lifetime, but I’m pretty sure this was a made for tv movie. It’s most likely from the 90’s, but possible late 80’s,  Here’s what I remember:

A girl gets killed by her boyfriend and he takes her out on a boat, and dumps her body in a lake.

This other girl – possibly her friend or relative, tries to solve the mystery of what happened to her. She finds a button on the dock by the lake and I think that’s how they find the dead girl’s body. the button is important, because it’s not a normal button. The girl had sewn it on her sweater herself, and it was in the shape of a flower or a bee or something.

I think the girl that died might have been pregnant too, and that’s the reason her boyfriend killer her, because she wanted to keep the baby. I might  be mixing that part up though.