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.
A lone wolf incident then. No radicalization or extremist ideology this time around.
And he was known to the authorities, but they declared him a good fella and let him go
Firearms instructor for the army so yea clearly wasn’t radicalized by terrorists. No siree.