JUDY WOODRUFF:

The death of a 25-year-old black man, Freddie Gray, in Baltimore is the most recent in a string of stories spotlighting use of force by police.

Many cities across the country are trying to improve relations between police and the citizens they protect. In Philadelphia, a recent Justice Department report found nearly once a week over the past eight years Philadelphia police opened fire on suspects, who are almost always African-American.

Hari Sreenivasan has more.

TANYA BROWN-DICKERSON, Mother of Brandon Tate-Brown: On December 15, 2014, I was going to work. I got to work a little late. I got there, I want to say 6:26. And I was getting ready to cut my car off. And I heard a black male, on the radio, a black male, 26 years old, gunned down by police at the 6600 block of Frankford Avenue, driving a white Dodge Charger.

So when I heard that, unfortunately, I knew that it was my son.