Want to show who was last responsible for "Potential Last Activity Time"

Want to show who was last responsible for "Potential Last Activity Time"

I want to list all Potentials by their Last Activity and by who carried out that Activity.

The "Potential Last Activity Time" I am using in a report works fine - I can list Potentials in order of most recent activities, including Notes being added. However, I also want to see who was the last person to carry out that Activity or Note addition. There doesn't seem to be a "Potential Last Activity By" which includes people who added Notes to a Potential. "Potential Modified By" and "Activity Created By" do not seem to include Notes being added to a Potential. Since most people add Notes when they follow up Potentials I really need to be able to include these. Any ideas?