Nakia Jones, a police officer from Ohio, went on Facebook Live on Wednesday to address Alton Sterling's fatal shooting by police officers in Louisiana.
Her video has been viewed 4 million times.
In the video Jones said: "If you are white and you work in a black community and you are racist, you need to be ashamed of yourself."
"If you are that officer that's prejudiced take the uniform off and put the KKK hoodie on," she said.
"You're afraid of people that don't look like you. You have no business in that uniform," she said.
Jones explained that she decided to work in a African-American community to make a difference.
"If it was my son, I don't know what I would do," she said.
She added: "We're killing each other. We have to stand together."
Many people shared Jones' video online with supportive messages.
BuzzFeed News has contacted Jones for more on her video and will update when she responds.