The most reliable way is to scan a profile on LinkedIn. In addition to basic information about work and education, you can find feedback from employers and partners. But I also use Google. A good specialist has publications in specialized media as well as experience of speaking at public events. If Google does not know him, then I doubt the professionalism of such a person.
Don't forget that:
Linkedin with 500+ means nothing. They can use fake accounts and they do it all the time. Linkedin with references to prior activities mean nothing. You can fake those too. Linkedin with links to other businesses don't mean anything. Other businesses can make fake sites just in order to support the scam.
Please google every member of the team. If they are nowhere to be found prior to the ico, bad news... If they do: check! Write emails and ask companies of they know them.
ICO-scammers know by now that the team is being checked. They go far in faking prior references.