Article content It’s a stark and alarming trend: Mass shooters engraving bullet casings with cryptic messages, leading officials to speculate about their motives and, more recently, their political affiliations. It happened in Dallas on Wednesday. Officials investigating an attack on an Immigration and Customs Enforcement facility that killed one detainee and critically injured two others announced that they had recovered unspent ammunition, with at least one labeled “ANTI-ICE.” Article content We apologize, but this video has failed to load. Try refreshing your browser, or tap here to see other videos from our team. Engraved bullet casings have become shooters’ manifestos...