Maine mass shooting: What we know about suspect Robert Card

A manhunt is underway for the suspect in a mass shooting in Maine that killed at least 18 people and wounded 13 others, officials said.

The mass shooting unfolded in two locations in Lewiston on Wednesday evening: a bowling alley where a children's league was taking place and a local bar, officials said.

The Androscoggin County Sheriff's Office released a photo Wednesday night of the suspect brandishing a semi-automatic rifle at one of the locations.

The suspected gunman -- identified as 40-year-old Robert Card -- is a U.S. Army reservist, the Army confirmed.

Authorities found the suspect’s white Subaru at a location in Lisbon, several miles southeast of Lewiston, late Wednesday, and recovered a firearm from the vehicle, multiple law enforcement sources told ABC News. Authorities are testing and tracing the gun to determine if it was involved in the shooting, according to the sources.

The abandoned car was a critical piece of evidence in allowing police to focus on Card, multiple law enforcement officials told ABC News.

Card's family is cooperating with authorities, law enforcement officials briefed on the investigation told ABC News. Card's sister told investigators she thought Card might have been looking for an ex-girlfriend at the shooting locations, the sources said. One avenue of investigation is whether this mass shooting began as a domestic dispute, according to the sources.

Card has been a U.S. Army reservist since December 2002, the Army said. His current rank is as a sergeant first class and his job is a petroleum supply specialist. He has no combat deployments.

A U.S. Defense Department official confirmed to ABC News that Card was "behaving erratically" while deployed over the summer with his Army Reserve Unit to Camp Smith Training Center in upstate New York to support summer training for West Point cadets.

Leaders of the Army Reserve's 3rd Battalion, 304th Infantry Regiment informed garrison staff at the training site about his behavior on July 17, the defense official said.

"Out of concern for his safety, the unit requested that law enforcement be contacted," the official said.

New York State Police officers responded and transported Card to Keller Army Community Hospital at the U.S. Military Academy for medical evaluation, the official said.

Card allegedly threatened other soldiers with violence and was “command directed” to go to the hospital for the evaluation, according to a source briefed and with direct knowledge of the incident.

New York State Police has stationed armed troopers at the entrances to Camp Smith as a precaution to beef up the armed security, according to the defense official.

An arrest warrant has been issued against Card for eight counts of murder for the victims who have been identified so far, officials said. The arrest warrant will be updated when the other 10 victims are identified.

"Mr. Card is considered armed and dangerous, and police advise that Maine people should not approach him under any circumstances," Maine Gov. Janet Mills said during a press briefing on Wednesday.

Maine officials did not speak to a potential motive, but said they are looking into Card's mental Health when asked during the press briefing about his background and gun possession.

"I know that we will be reviewing that information as we move forward, but that's not an answer that we're prepared to give today," Maine Department of Public Safety Commissioner Mike Sauschuck said.

"There’s still an active search for the suspect in question," he said.

Card was not assigned to West Point as any sort of instructor, including firearms, an academy official told ABC News.

"While his unit supported West Point summer training, our records indicate he did not instruct nor have any interactions with cadets in training," the official said.

Card's Military service awards include the Army Achievement Medal, Army Reserve Component Achievement Medal, Humanitarian Service Medal, National Defense Service Medal and Army Service Ribbon.

ABC News' Josh Margolin, Aaron Katersky and Luke Barr contributed to this report.