"Who Framed Me?" (Only a beginning because I can't think of the rest of the song.)

Hello! I've been with Musescore for about 3 years now and I've never been a good song writer. But after hearing this in my head I've made only the beginning for a jazz song, The only type of music I write. I know this is kind of broad but I'm asking if anyone can help me on a melody and then a harmony. I always screw up if I try to do it by my self. Is anyone willing to help me? I want this to be a full jazz song one day!
https://musescore.com/user/4879056/scores/2615441
Feel free to type suggestions in the comments!