No, there wasn't a 'reasonable' suspicion. It was actually driven hard as a land and property grab by corrupt California politicians and real estate speculators.
There were more Japanese people in Hawaii than California, yet they didn't intern them all there.
No they didn't intern them all in Hawaii, but they did intern some. 1/3 of the island was Japanese. But it's an island. They didn't have easy access to the mainland. The Japanese in California did, and that's probably the basis of the decision.
Our "politically correct" failure to segregate the muslims in the military during our War on Terror in the middle east resulted in American deaths. 13 dead and 30 wounded by the Fort Hood muslim.