In this April 26, 2008 file photo, Prince performs during the second day of the Coachella Valley Music and Arts Festival in Indio, Calif. A law-enforcement official says that tests show the music superstar died of an opioid overdose. Prince was found dead at his home on April 21, 2016, in suburban Minneapolis. He was 57. (AP Photo/Chris Pizzello, File) 

This undated file photo released by Javille Burns shows her brother, Jamar Clark, who was shot Nov. 15, 2015, after a confrontation with two police officers and died a day later. Minnesota U.S. Attorney Andrew Luger on Wednesday, June 1, 2016, declined to file civil rights charges against Minneapolis Officers Mark Ringgenberg and Dustin Schwarze in Clark’s death that sparked weeks of protests. Luger said in a news release that there's insufficient evidence to support the charges. (Jamar Clark/Javille Burns via AP, File) 

Philadelphia police Officer Eric Tyler poses for a photograph, Thursday, May 26, 2016, in Philadelphia. Tyler was recognized for using a stun gun instead of a real gun on a suspect who threatened to shoot his colleague in February. Tyler, who has never shot anyone in his 12-year career, said he considered using deadly force but made a split-second decision not to. More than 40 Philadelphia officers have received awards since December for defusing conflicts without shooting, clubbing or otherwise using maximum force against anyone. The awards reflect an increasing emphasis on “de-escalation” in police work. (AP Photo/Matt Rourke) 

In this April 12, 2016 photo, Jennifer Dumas looks out the window with her daughter, Codylynn, inside her room at Bedford Hills Correctional Facility, in Bedford Hills, N.Y. Bedford Hills has one of only eight working prison nurseries where women live with their babies, out of more than 100 women's prisons around the country. (AP Photo/Julie Jacobson) 

Washington DC weed festival 

This undated photo made available by the Georgia Department of Corrections, shows Timothy Tyrone Foster. The Supreme Court has thrown out a death sentence handed to Foster because prosecutors improperly kept African-Americans off the jury that convicted Foster of killing a white woman. The justices ruled 7-1 Monday, May 23, 2016. The outcome probably will enable Foster to win a new trial, 29 years after he was sentence to death. (Georgia Department of Corrections via AP) 

Bill Cosby departs the Montgomery County Courthouse after a preliminary hearing, Tuesday, May 24, 2016, in Norristown, Pa. Cosby was ordered to stand trial on sexual assault charges after the hearing. (AP Photo/Matt Rourke, Pool)