After more than a decade of decline, violent crime in Los Angeles rose more than 20 percent in the first half of this year, with felony assaults up 26 percent and robberies up 19 percent. No one knows why, but there’s plenty of speculation, writes Joe Domanick, West Coast bureau chief of The Crime Report, in the Los Angeles Times. Criminologists say crime goes up and down, and sometimes it’s a trend, or just a blip, apart from what the police are doing. Violent crime in cities like Los Angeles may have plunged to historic modern lows and simply bottomed out.