Investigators do not believe suspect Robert Card's motives behind the mass shooting are linked to domestic terrorism, law enforcement sources briefed on the investigation told ABC News.

Maine authorities are telling their law enforcement partners there is no known connection to domestic terrorism or homegrown violent extremism, preliminary ruling out a possible motive as investigators continue to develop a fuller picture of the suspect, according to the sources.

-ABC News' Aaron Katersky

U.S. Rep. Jared Golden, (D-ME), announced that he was changing his policy against an assault rifle ban during a news conference with other Maine congressional leaders Thursday evening.

Golden was one of five Democratic House members who voted against a ban in 2022. Although the bill passed 217 -213, it did not move forward in the Senate.

Golden said the shooting has made him change his stance and will now support any measures in Congress that ban assault weapons.

"I ask for forgiveness and support as I seek to put this end to these terrible shootings," he said.

Sen. Susan Collins, (R-ME), told reporters that although she wanted to see more gun control reforms, such as a ban on high-volume magazines, she did not support an assault rifle ban.

Although Collins said she didn't know the circumstances as to how the suspect, who has had reported mental health issues, was able to commit the shooting, she said more should have been done.

She cited the state's "yellow flag" law, which gives law enforcement the authority to request a court to remove firearms from someone who has mental health problems.

"It certainly seems that on the basis of the facts that we have, the yellow flag law should have been triggered," she said.

The U.S. Army released a statement Thursday evening about suspect Robert Card’s service record and refuted reports that he served as a firearms instructor.

Card was a reservist and assigned to the 3rd Battalion, 304th Infantry Regiment in Saco, Maine which had a training at West Point over the summer, according to Army spokesperson Bryce Dubee.

"While his unit supported West Point summer training in July of 2023, there are no records to indicate he instructed or participated in any training," Dubee said in a statement. "The Army did not train SFC Card as a firearms instructor, nor did he serve in that capacity for the Army."

-ABC News' Luis Martinez

Dr. John Alexander, the chief medical officer of the Central Maine Medical Center, which admitted 14 victims from Wednesday's mass shooting, spoke with ABC News' Trevor Ault about the scramble his physicians made to treat the patients.

Three of the patients died and another three are in critical condition as of Thursday evening.

Alexander said although the team is trained to deal with mass casualty events, the number of casualties was a challenge for the hospital.

“It certainly is unprecedented so far as the severity of the injuries and certainly the attack on the community,” he said.

At least 30 to 40 employees who were not on shift last night were voluntarily standing by to assist fellow staffers working around the clock to care for victims, according to Alexander.

He said the hospital is providing 24-hour mental health resources for staffers in need.

-ABC News' Briana Stewart

Gov. Janet Mills officially confirmed the Maine mass shooting suspect Robert Card is dead. Authorities found his body on Friday, she said.