Lewiston attack: What we know so far about Maine mass shooting

Authorities are focusing their attention on the Androscoggin River, close to where the suspect's car was found.

The massive manhunt for the US Army reservist accused of killing 18 people in the American state of Maine continued Friday with a focus on the boat launch where police discovered his car.

Maine Safety Commissioner Mike Sauschuck said he intended to direct divers, helicopters and officers to the Androscoggin River and the shoreline.

"I'm not saying the suspect is definitely in the water," he told reporters.

The alleged gunman is said to have entered a bowling alley and then a restaurant in Lewiston and opened fire indiscriminately in both locations on Wednesday evening.

Here's what we know about the hunt for the murder suspect.

The police manhunt

Mr Sauschuck said they were working the river because of the car's location and the fear they might lose evidence in the current.

But authorities are not limiting the manhunt to the river.

Almost exactly 24 hours after the two shootings, police executed a series of search warrants on a rural road in a small Maine village the suspect called home.

Part of that effort in Bowdoin was caught on live TV as police were heard yelling over a megaphone for Mr Card to surrender and come out of a house "with your hands up".

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Police later said that this was a standard search warrant announcement made before entering a house, but it was "unknown whether Robert Card is in any of the homes law enforcement will search".

Mr Sauschuck said that they were working to acquire further search warrants to obtain "phones and computers from other locations.

The federal government may also be helping with that aspect of the search, according to Miles Taylor, the former Chief of Staff to the Department of Homeland Security.

Mr Taylor told the BBC that the federal government has access to technical and electronic tools "that might help track down this subject, or figure out where he was in the hours ahead of this attack, or potentially, to understand what his motivations and planning were".

Who are the victims?

We do not have many details yet on the people killed or injured, but we do know that seven died in the shooting at the bowling alley.

Witnesses described families being there at the time and the panic that was triggered by the gunshots.

Riley Dumont told ABC News her 11-year-old daughter had been taking part in a children's bowling league when the gunman opened fire.

She ended up laying on top of her daughter to shield her from the bullets, and her mother lay on top of her.

Eight people, all male, were killed at the Schemengees Bar and Grille restaurant, seven inside and one outside, police said.

Some of the dead have been identified and their families informed, but there are 10 people still unidentified.

Who is suspect Robert Card?

The police named Robert Card as the suspect and described him as 5'11" (180cm) tall, weighing 230 pounds (104kg).

He is armed and dangerous, police said, but they have not said anything about a possible motive.

Police said he spent two weeks at a mental health facility this summer and was subsequently released. He was removed by New York State Police from a training exercise at the US Military Academy in July for "behaving erratically," the service said.

"He was picking up voices that he had never heard," his sister-in-law Katie Card told NBC News. "His mind was twisting them around. He was humiliated by the things that he thought were being said."

His last known address was in Bowdoin, Maine.

He attended the University of Maine as an engineering student. It is not clear if he graduated from the university.

Mr Card is enlisted in the US Army Reserve and has an active military ID, the US Army confirmed.

Authorities initially described him as a trained firearms instructor but later said that was not accurate. An Army spokesperson said the service had not trained Card "as a firearms instructor, nor did he serve in that capacity for the Army".