ProtonMail CEO Andy Yen (former CERN physicist): http://inspirehep.net/search?ln=en&p=Andy+Yen&of=hb&action_s...
ProtonMail CTO Bart Butler (also former CERN physicist): http://inspirehep.net/search?ln=en&ln=en&p=bart+butler&of=hb...
TED Talk about ProtonMail given by ProtonMail CEO: https://www.ted.com/talks/andy_yen_think_your_email_s_privat...
So the evidence that ProtonMail is run by former CERN researchers is actually quite overwhelming.