Last spring, a 25-year-old African American man named Freddie Gray was arrested and put in the back of a police van in Baltimore. By the time the van reached its destination, Gray had fallen into a coma. Just days later, he died from injuries to his spinal cord.

Today, after a year-long investigation, the Department of Justice issueda report saying the Baltimore police department systematically discriminated against black residents and failed to adequately discipline cops who crossed the line.

The numbers, according to homeland security expert Juliette Kayyem, are "jaw-dropping." In a city that is 63% black, 91% of people arrested for discretionary offensives like failure to obey or trespassing are black. Blacks make up 60% of the city's drivers but account for 82% of traffic stops. Of the 410 pedestrians stopped at least ten times in the five years' worth of data reviewed, 95% were black.

"Freddie Gray is the big case that people get outraged about, but when you think of the day-to-day experience of African Americans with the Baltimore Police Department, the numbers don't lie," Kayyem said.

Kayyem said the report is the first step in a long rectification process, and will provide Baltimore mayor Stephanie Rawlings-Blake and other local leaders with the evidence they need to force change.

"Now she can seek both the civilian oversight the police department is going to need, more aggressive training, and other aspects," Kayyem said.

But much of that change will have to come from within Baltimore's police, Kayyem added.

"It's going to come from police departments getting rid of bad actors in a public manner. The more this festers, it's viewed as acceptable behavior," Kayyem said.

To hear more from Juliette Kayyem, tune into Boston Public Radio above.