The man suspected to be behind the mass shooting in the US region of Maine was found dead following a three-day manhunt.

Androscoggin County Sheriff's Office posted on Facebook: "The suspect in Wednesday nights shootings has been located and is deceased."

Robert Card, 40, was found dead from an apparently self-inflicted gunshot wound, Maine Commissioner of Public Safety Michael Sauschuck was quoted as saying by BBC.

Maine Governor Janet Mills later released a statement and said: "Like many Maine people, I breathe a sigh of relief knowing that Robert Card is no longer a threat to anyone else. I know there are many people who share that sentiment. I also know that his death may not bring solace to the victims of this tragedy."

"While this search has concluded, I know that law enforcement continues to fully investigate this tragedy so that we can bring what closure we can to the victims and their families. I ask that all Maine people continue to keep those families, and all of the people impacted by this tragedy, in their thoughts," she said.

A three-day manhunt was launched recently after the suspect killed 18 people in a mass shooting incident.