Police were searching late Saturday night for a 38-year-old man, believed to be armed and dangerous, in the shooting death of a woman in the Aroostook County town of St. Francis.

The search began Saturday when the Aroostook County Sheriff’s Office received a 911 call at 5:45 a.m. about a domestic violence incident at 754 Main St. Before arriving, police learned that Amy Theriault, 31, longtime girlfriend of Marquis, had been shot and killed.

Witnesses in the home said they saw Marquis leave the residence and enter the woods behind the house with a rifle.

Maine State Police, the Aroostook County Sheriff’s Office, the U.S. Border Patrol and U.S. Customs and Border Protection are searching for Marquis. He is 5 feet, 7 inches tall, 150 pounds, with black hair and blue eyes. He was wearing blue jeans, a green hooded sweatshirt and a Cabela’s ball cap. Marquis was last seen entering the woods on the south side of Route 161 in St. Francis.

Maine State Police is asking for the public’s help in locating Marquis. Anyone who sees Marquis or someone matching his description is asked to call state police in Houlton at 532-5400 or Aroostook County Crime Stoppers at 1-800-638-8477.

Police strongly recommend that no one approach Marquis.