California reels from back-to-back shootings that killed 18

A deadly gun rampage at northern California mushroom farms likely stemmed from a workplace grievance, authorities said on Tuesday, as new details emerged about the latest of two back-to-back mass shootings that claimed 18 lives in total.

In apparently unrelated acts of mass murder, 7 people were killed on Monday in an attack on farm workers, many of them immigrants, in the seaside town of Half Moon Bay near San Francisco while 11 people were shot to death on Saturday night at a Los Angeles-area dance hall frequented mostly by older patrons of Asian descent.

The suspects in both attacks were men of retirement age, much older than typical perpetrators of deadly mass shootings that have become all too common in the United States.