Such sad news, RIP both riders & I hope they do discover the unknown's indentity soon
I have a specific wallet I use while cycling, it has my CTC, YHA membership cards in it, an ICE card & of course my Visa! So, if the worse was to happen I'm hoping this would be enough info.
When I rode the Capital to Coast in the summer, we all had stickers on our bikes with our name on it & an emergancy name/contact number. I never removed mine as figured it was a great idea, i've also printed off a couple of others & stuck them on my other bikes.