Lewiston police have identified Robert Card, 40, as a person of interest following one of the deadliest mass shootings on US soil.

Police are urging the public to contact law enforcement if they have information about Card’s whereabouts.

Law enforcement officials in Maine told CNN that Card is a certified firearms instructor and a member of the US Army Reserve.

Police found a white SUV they believe Card drove to the town of Lisbon, about 7 miles (11 km) to the southeast, and Sauschuck said people were asked to remain indoors in both Lewiston and Lisbon.

Maine public safety official Mike Sauschuck told reporters: “Card is considered armed and dangerous.

“He is a person of interest, however, and that’s what we’ll label them at moving forward until that changes. If people see him, they should not approach Card or make contact with him in any way.”

“We have literally hundreds of police officers working around the state of Maine to investigate this case, to locate Mr Card, who, again, is a person of interest, and a person of interest only.”