(NewsNation) — The man who killed 18 and wounded 13 others in Lewiston is dead, but investigators and state officials are still trying to determine what led up to the massacre and how to prevent another from happening.

After a two-day search, Robert Card’s body was found late Friday in a trailer at a recycling center in Lisbon Falls.

On Monday, Maine Gov. Janet Mills vowed to have a “thoughtful and comprehensive discussion” with state legislators, public safety officials and other experts to address gun violence.

“I believe action is needed – what that action will be must be the product of a broad discussion among a diverse group of voices,” Mills said. “The people of Maine deserve this.”

The governor said state lawmakers would revisit Maine’s gun control laws but did not outline specific proposals.

Meanwhile, investigators are still trying to determine a motive for the attacks. So far, law enforcement officials have focused on Card’s history of mental health issues and cited his paranoia as a likely factor.

Five months before the shootings, Card’s own family alerted the local sheriff that they were concerned about his deteriorating mental health and access to guns.

It’s still unclear whether the 40-year-old gunman, who was in the Army Reserve, planned the attacks in advance or knew any of the victims.

Nearly three months ago, Card tried to acquire a gun silencer, also known as a suppressor, but was denied due to his mental health background, the Associated Press reported.

So far, there’s no evidence Card had been involuntarily committed to a mental health facility, State Department of Public Safety Commissioner Michael Sauschuck said Saturday.

Authorities have recovered several weapons that they believe Card legally purchased. A Ruger SFAR rifle was found in his car and two others, a Smith & Wesson M&P .40 caliber handgun and a Smith & Wesson M&P 15 rifle, were found with his body, the Maine Department of Public Safety said Monday.

Testing still needs to be done to confirm whether those guns were used in the shootings.

Both the crime scenes, one at Just-in-Time Recreation and the other at Schemengees Bar and Grill, have been processed and turned back over to the owners, officials said.

Governor Mills has announced a number of support resources for those impacted by the shootings, including a family assistance center as well as a mental health assistance center in Lewiston.

Anyone looking for information on how to help can learn more here.

President Joe Biden is likely to visit Lewiston sometime this week, the Portland Press Herald reported.