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 and never should have been given a badge and gun to patrol American streets, several of his close relatives told The Associated Press.David Brouillette, 37, has a history of terrifying and violent behavior, according to those relatives. They accuse him of attacking women in his life over the years, and one shared a voicemail with the AP from last winter in which he told her that he thought someone should slit her throat.CBS News also spoke with one of those relatives, his ex-wife Ashley Brouillette, who said that given his history, she didn't believe him when he told her last November that he'd been hired by ICE."I don't understand how he keeps getting these jobs where there are firearms involved. He's a danger to society. He's a danger to people and to himself," she said. "And I just don't understand how he keeps getting away with it." David Brouillette's troubling past further challenges how thoroughly the Department of Homeland Security has vetted recruits as it went on a hiring spree to help carry out President Trump's immigration crackdown.At least 10 people have died in encounters with immigration agents since Mr. Trump launched the crackdown after retaking office, including 25-year-old Johan Sebastián Durán Guerrero, a Colombian national who was shot and killed by Brouillette on Monday while in his car near his home in the coastal Maine city of Biddeford. That incident came just days after an ICE officer shot and killed a man in Houston, 52-year-old Lorenzo Salgado Araujo.DHS, which hasn't released the name of the officer who killed Durán Guerrero, has said the "vehicle attempted to flee the scene and, fearing for public safety, an officer discharged his weapon."