Reporting images/videos on porn sites to the AFP- stumbling across very upsetting things...

Hubby and I occasionally jump online and open a 'incognito' browser through chrome, and via a secure VPN and watch a bit of porn.
We do this so no one will ever stumble across it when using our laptop (kids, family, the IT guy).
But recently we've stumbled across very horrible stuff, not watched ANY of it, totally absolutely not what we are looking for and it has made our stomached churn, but things involving kids and incest and along those lines.
I feel so upset at the fact that these horrific things actually happen every day, but to just have them pop up for people to click on at standard porn sites, AT ALL!! What is wrong with this world!!
Anyway, I really want to report any and all of these horrific links to the police. I have to do something now I've come across it- even if it only ever helps one child it's worth it.
Do you know how I would go about doing this?
I feel slightly concerned that they might think I'm looking for these things- please understand- could not be more from what we were looking for.
I'm not okay with doing nothing, and while I know there are task forces set up to search the net and remove these horrific images and videos and catch these monsters- they can't get to them all.
I have children- I believe in protecting children at any cost.
No negative comments please, as I have explained this was absolutely NOT what we intended to find when we typed in 'husband wife real style porn'.
Thank you for taking the time to read and respond.