Robert Card committed the deadliest mass shooting in Maine history when he killed 18 people at a bowling alley and a bar on Oct. 25 in Lewiston.
The Army recently determined that the gunman should not have access to firearms.
Authorities scoured the woods and hundreds of acres of family-owned property, and sent dive teams with sonar to the bottom of a river.
“He died as a hero,” said the father of Joe Walker, who charged at the shooter with a knife during Wednesday night's attack in Lewiston.
Hundreds of law enforcement agents, including dozens of FBI agents, have been hunting for suspect Robert Card since Wednesday night’s shootings.