Three Children Attacked a Black Woman. A Sheriff’s Deputy Arrived — and Beat Her More.

The Jefferson Parish Sheriff’s Office is investigating a deputy accused of holding a Black woman by her hair and slamming her head repeatedly into the pavement with such force that a witness to the Sept. 20 incident said it ripped several of Shantel Arnold’s braids from her scalp. A 14-second video captured the incident in the New Orleans suburb where, for decades, Black residents have accused the Sheriff’s Office of targeting them.

It was the second time that hour that Arnold had been assaulted. By the time the deputies arrived, she said...