In the movie Before we vanish we see the reporter Sakurai meeting and helping the alien Amano in his quest to find Akira. At the beginning out of curiosity and seemingly disbelief, but later he seems quite convinced that they're real aliens planning to invade our planet.
Why does he continue helping them? He himself says after seeing one of the aliens killing a human "I'm still on the human's side". They explain to him that after the invasion all human life will end, except for a few specimens for sampling. They seem to trust him to get close enough and he had a few opportunities to kill them and/or try to stop the invasion.
Why would he continue to help them with a plan to kill all humans?