OXFORD, Maine (AP) A Maine hunter charged with killing a woman he mistook for a deer has been formally charged with manslaughter.

An Oxford County grand jury returned the indictment against 38-year-old Robert Trundy of Hebron. The Bangor Daily News reports that he’ll be arraigned on March 9; it wasn’t immediately known if he had a lawyer.

The shooting happened Oct. 28, the first day of deer hunting season for Maine residents.

The 34-year-old victim, Karen Wrentzel, was digging for gemstones on her property when she was shot. In an affidavit, Trundy told game wardens he thought he was firing at a deer, and his attorney said that the shooting wasn’t reckless.

Wardens say he fired from 200 feet away. If convicted of manslaughter, Trundy faces up to 30 years in prison.