Robert Card, the suspect in the shootings Wednesday that killed 18 in Maine, received inpatient psychiatric care this past summer after he started hearing voices, according to his sister-in-law, Katie Card.

Maine Gov. Janet Mills said at a press conference Thursday that 18 people were killed and 13 people were injured in the attacks Wednesday night. Maine State Police worked through the night alongside local officers and the Federal Bureau of Investigation to attempt to find Card, 40 years old, their sole named suspect.