The Immigration and Customs Enforcement officer who shot a Colombian man in Maine this week is an Army veteran who has struggled with serious mental health issues since early childhood, according to close relatives who spoke to The Associated Press.

The Maine Attorney General’s Office said it was investigating “a fatal use of deadly force” involving federal law enforcement.

Protesters in Maine gathered outside Senator Susan Collins’ office to demand justice for the 26-year-old Colombian man who was fatally shot by federal agents