The families of Alton Sterling and Philando Castile want answers and justice.
But as we've seen in Ferguson, New York City, and Baltimore every case is different.
FOX 2 Legal Analyst Charlie Langton weighs in.
"I think the Department of Justice is going to get into both of these cases," he said. "What they are looking for are two things - was there criminal intent on the part of the officer and the other element is reckless disregard for human life - and it has to reach a level worse than carelessness."
He said that is the focus of prosecutors in both cases.
Another element is the cell phone video in the Sterling and Castile incidents.
"This will be exhibit 1 in an investigation certainly exhibit 1 in a trial," Langton said. "You don't need a lot of witnesses when you have video. Is the video complete, no. That's the art of a good defense attorney or prosecutor is to tell the jury is to tell what happened before. It is very difficult.
"And these videos are very compelling pieces of evidence."
For more of Langton's breakdown, watch the video above.