So here is a list of free software you can use for you investigations.
Audacity - This is good software to listen to your recorded information. It's available for Windows, OSX and Linux.
Davinci Resolve - This is high end editing and color correction software. They offer a free version if you scroll all the way down to the bottom of the page. I've just downloaded the software and will start testing it out to see what the learning curve is. It's available for Windows and OSX. Stay tuned.
Blender - This is 3D software but also comes with a video editor. It's available for Windows, OSX and Linux.
Gimp - Gimp has been around for a while. It's open source and volunteer developers maintain it. It's available for Windows, OSX and Linux.
Photoscape - A basic photo editor that let's you create slide shows and animated GIFs as well. It's available for Windows and OSX.
The Nick Collection - A fill image-editing suite by Google. Doesn't look like Google is going to offer updates or patches so this might not have a long use life. It's available for Windows and OSX.
Paint.net - Image editing software with layers and unlimited undos. Windows only.