On Tuesday, Alton Sterling of Baton Rouge, Louisiana, was fatally shot by police outside a convenience store where he had been selling CDs.
Several videos of the incident show two police officers tackling Sterling to the ground and shooting him in the back and chest multiple times. The Department of Justice and the FBI are investigating the case.
The following night, Diamond "Lavish" Reynolds uploaded a live video to Facebook showing her boyfriend, Philando Castile, after he had been shot by police in St. Paul, Minnesota, during a traffic stop.
Castile, 32, later died at the hospital. His 4-year-old daughter was in the backseat of the car when police shot him.
Reynolds said during a news conference Thursday that she wanted the video of her boyfriend's death to go viral.
“I wanted everyone in the world to know how much [the police] tamper with evidence and how much they manipulate our minds," she said. "I wanted it to go viral so that people could determine themselves as to what was right and what was wrong."
Here's how some people on Twitter have reacted to the police shootings.
Beyoncé also posted a call to action on her website called "Freedom."
"We're going to stand up as a community and fight against anyone who believes that murder or any violent action by those who are sworn to protect us should consistently go unpunished," she wrote.