The suspect is believed to be Robert Card, a 20-year US Army veteran from Bowdoin Center, Maine.
(according to Telegrams so take with grain of salt)
EDIT: Name confirmed by news.
According to law enforcement, CARD recently reported mental health issues to include hearing voices and threats to shoot up the National Guard Base in Saco, ME.
having lived in rural maine, yes the nature was beautiful but socially it was pretty depressing and impoverished, but not a lot happens there so an 80-person mass shooting - I’m both really surprised and not very surprised at the same time :/