(CNN) — A US Army reservist accused of killing 18 people and injuring 13 others in a shooting rampage in Maine this week was found dead Friday evening – apparently from a self-inflicted gunshot – after a two-day manhunt, a state official said.

Robert Card, accused of committing Wednesday’s massacre at a bowling alley and a restaurant in Lewiston, Maine, was found dead around 7:45 p.m. Friday near the Androscoggin River in the Lisbon Falls area, some 10 miles Lewiston, state Public Safety Commissioner Michael Sauschuck told reporters.

Maine Gov. Janet Mills said she is “breathing a sigh of relief tonight knowing that … Card is no longer a threat to anyone.”

“Now is a time to heal,” Mills, who said Maine State Police found the body, told reporters at the news conference. “Tonight, the city of Lewiston and the state of Maine begin to move forward on a long road to healing.”

Card’s body was found in an area near a recycling center from which he had recently been fired, a law enforcement source told CNN. Earlier this week, authorities had found Card’s vehicle abandoned after the shooting near a boat launch in the Lisbon area.

Details about when Card died still were being investigated, Sauschuck said, and authorities haven’t announced a motive in the shooting. Authorities intend to release more information Saturday morning about Card and the investigation, they said.

The discovery of Card’s body ends an intense two-day search that saw hundreds of officers scour parts of southern Maine by land, water and air, and finishes a period in which communities were simultaneously grieving and riddled with anxiety about the suspect’s location. Shelter-in-place orders for Androscoggin and northern Sagadahoc counties were in place from Wednesday night until they were lifted Friday afternoon, and schools, businesses and facilities were closed much of that time.

Part of the reason the search for Card was expanded to waterways: Authorities found a note from Card that indicated that he did not expect to be alive when the note was found, a law enforcement official told CNN.

The note essentially gave information to others about where things could be found and how things could be disposed of, the official said. Authorities had executed at least three search warrants Thursday on his vehicle, home and another property, the source said, which informed their search procedures Friday.

Wednesday evening’s shooting was the deadliest US mass shooting since last year’s massacre at a school in Uvalde, Texas.

Sources: Suspect bought gun legally days before psychiatric evaluation

Earlier Friday, multiple law enforcement sources told CNN the gun investigators believe Card used to carry out the massacre was purchased legally just days before he was hospitalized and ordered to undergo a psychiatric evaluation in July.

In mid-July, New York State Police were called to Camp Smith in Cortlandt, New York, the military base where Card served, because he was acting “belligerently and possibly intoxicated,” according to a source briefed on the matter. Three law enforcement sources confirm state police brought Card to a nearby hospital, where he was treated for suspected intoxication and released the next day. When asked for information about the encounter, a New York State Police spokesperson told CNN: “This is an active investigation, and the New York State Police does not comment on active investigations.”

A federal law enforcement source told CNN the army gave Card a “Command Referral” to seek treatment after he told army personnel at Camp Smith Card had been “hearing voices” and had thoughts about “hurting other soldiers.” A National Guard spokesperson confirmed to CNN Card was transported to the nearby Keller Army Community Hospital at the United States Military Academy for “medical evaluation,” after Army Reserve officials reported Card for “behaving erratically.”

Card’s encounters with New York State Police and his National Guard superiors occurred just 10 days after Card had purchased the high-powered rifle at a Maine gun store, according to law enforcement sources. The rifle was a Ruger SFAR chambered for high-powered .308 ammunition, the sources added. The .308 round is favored by military snipers firing at long distances and big game hunters. It is larger and more powerful than the regular ammunition carried in the rifles of soldiers and SWAT teams.

Sources say the weapon found inside Card’s 2013 white Subaru Outback appears to be the same one fired by the gunman at the bowling alley and a local bar, though a ballistics match has not been confirmed. The weapon will be processed by the FBI and ATF for fingerprints and DNA and then run through laboratory testing to determine if the bullets and shell casings found at the scene match.

In the same July purchase, along with the rifle, sources say Card also bought a Beretta 92-F 9mm semi-automatic pistol. It is the standard pistol of the US military.

Deceased victims were 14 to 76 years old

The horror began around 7 p.m. Wednesday in Lewiston, where authorities say Card opened fire at Just-in-Time Recreation and then later at Schemengees Bar & Grille. Police were on the scene within just minutes of 911 calls made from the shooting locations, they said.

In addition to the 18 people killed, 13 others were injured, the Maine governor said Thursday.

Authorities identified all deceased victims Friday and said all their families had been notified. The oldest killed was a 76-year-old man and the youngest was a 14-year-old boy bowling with his father.

The victims are Tricia Asselin, William Frank Brackett, Peyton Brewer-Ross, Thomas “Tommy” Conrad, Michael Deslauriers II, Jason Walker, Keith Macneir, Bryan MacFarlane, Ronald “Ron” Morin Arthur “Artie” Strout, Joseph “Joey” Walker, Joshua Seal, Maxx Hathaway, Robert “Bob” Violette, Lucille Violette, Stephen “Steve” Vozzella, William “Bill” Young and his son Aaron Young.

Sources: Investigators developed working theory on why locations were targeted

Authorities searched two days across southern Maine for the suspect. Before Card’s body was found, authorities Friday still were urging residents across a 700-square-mile area to be vigilant as authorities raced to apprehend him.

Live Updates: Manhunt continues after Maine shooting rampage

Before Card was found dead, investigators had recovered a cell phone that belonged to Card, a law enforcement official said Friday. It added to the challenges for investigators, who routinely track cell phones to find suspects.

During the search, a CNN team saw officers surrounding a greenhouse late Friday morning at Springworks Farm in Lisbon, which is less than a mile from a boat launch where Card’s vehicle was found. Officers cleared the scene by noon.

And while the motive for the massacre remained unannounced Friday evening, a key theory about why the bowling alley and the restaurant were targeted emerged during the investigation, law enforcement sources say.

Card recently broke up with a longtime girlfriend, and investigators are pursuing a theory that Card went to the bowling alley and the bar because they were places the couple used to frequent, law enforcement sources told CNN’s John Miller.

Investigators believe the ex-girlfriend had signed up to play in a tournament at the bar Wednesday night, the sources said. According to the Facebook page for Schemengees Bar and Grill, Wednesday is “Industry Night,” which draws employees from other bars and restaurants in the Lewiston area.

Now that authorities know Card is dead, a hunting restriction that was in place for four communities because of the manhunt has been lifted, Sauschuck said Friday night. The lifting of the restriction in Lewiston, Lisbon, Bowdoin and Monmouth comes in time for Saturday’s opening of Maine’s rifle hunting season.

A fellow Army Reserve member said Card was a skilled marksman

Card was a petroleum supply specialist in the Army Reserve and first enlisted in 2002, according to records provided by the Army. 

Even though he was a certified firearms instructor, law enforcement officials told CNN, his time in the Army did not include training as a firearms instructor “nor did he serve in that capacity for the Army,” spokesperson Bryce Dubee said in a statement to CNN.

Still, Card had extensive training, including land navigation, making him “very comfortable in the woods,” said Clifford Steeves, who told CNN he knew Card when they both served in the Army Reserve.

He said Card is a skilled marksman who was one of the best shooters in his unit.

Investigators searched the suspect’s car Thursday and recovered a .308-caliber AR15 rifle. The Bureau of Alcohol, Tobacco, Firearms and Explosives will conduct tests to determine whether the gun can be matched to bullets and shell casings recovered at the two shooting scenes.

Steeves met Card in the early 2000s when they served together and knew him until about a decade ago, he said. Steeves said he didn’t notice any concerning behavior from Card, who he described as an “outdoors type of guy.”

“He was a very nice guy – very quiet. He never overused his authority or was mean or rude to other soldiers,” Steeves said. “It’s really upsetting.”

Katie O’Neill, Card’s sister-in-law, told CNN he didn’t have a long history of mental health challenges.

“This is something that was an acute episode. This is not who he is,” O’Neill said, referring to his July hospitalization. “He is not someone who has had mental health issues for his lifetime or anything like that.”

CNN’s Shimon Prokupecz, Andy Rose, Travis Nichols, Amanda Jackson, David Williams, Caroll Alvarado, Eric Levenson, Maria Santana, Haley Brtizky, Joe Sutton, Sara Smart, Brian Todd, Macie Goldfarb, Maria Sole Campinoti, Chris Boyette, Sara Smart, and Zoe Sottile contributed to this report.