A political ad from President Donald Trump that shows a Mexican immigrant bragging about killing police officers has put the spotlight back on noted immigration hard-liner Joe Arpaio, who detained and released the man in the video years ago. The former six-term sheriff of metro Phoenix says he’s being unfairly blamed for releasing the immigrant depicted in the video that has stoked immigration anxieties in the days leading up to the midterm elections. The ad centers on Luis Bracamontes, who was convicted of murder in the 2014 shooting deaths of two sheriff’s deputies in California while he was in the...