When Prohecy Fails - SLRPNK

I’m reading this book about social researchers who infiltrated into a cult and were observing their ups and downs. The story took place in 1950th by the way. At some point the group’s popularity spiked and various media and news papers all across the country were drawn to it. I grew curious about what they looked like and thought that some photographs would likely be there because of the media coverage, but found none. Do you have any hints where I should look up besides Google