Killings in L.A. spike dramatically, leaving families shattered, communities reeling

Beneath a highway overpass in South Los Angeles on Saturday night, a detective clicked his flashlight on and off as he carefully placed a yellow evidence marker in the middle of the street and then another closer to the curb, near the pooled blood of a 17-year-old boy.

A big dog barked behind a nearby fence as another detective recounted for his colleague how the teenager had been riding a bicycle when he was gunned down. The boy died en route to a hospital.

His death and three other fatal…