Demonstrators rally at city hall in Baltimore, Maryland May 3, 2015. [Photo/Agencies]

State's Attorney Marilyn Mosby has said Gray died after suffering a broken neck while inside a police van. On Friday, Mosby filed charges against the officers involved in his arrest and transport. One is charged with second-degree murder. Three others are charged with involuntary manslaughter and two with second-degree assault.

Mosby said Gray's neck was broken because he was placed head-first in a police van, handcuffed and later in leg shackles, where he was left to slam against the walls of the small metal compartment. Police said the officers who arrested Gray ignored his cries for help because they thought he was faking his injuries. He was repeatedly denied medical attention.

Rioting and looting erupted hours after Gray's funeral last Monday. A 10 pm-5 am curfew was ordered Tuesday after a night of violence and arson. About 3,000 National Guard soldiers were deployed to the city along with 1,000 extra police officers, including some from out of state. Republican Gov. Larry Hogan said the Guard and the officers would be leaving over the next few days.

"We think it's time to get the community back to normal again,'' Hogan said. "It's been a very hard week, but we've kept everybody safe.''

The Maryland chapter of the ACLU sent a letter to Rawlings-Blake on Saturday alleging that the curfew was "being enforced arbitrarily and selectively'' to break up peaceful protests and prevent media outlets from providing accurate coverage of police activity.

"The curfew is having a dramatic effect on the ability of Baltimore residents to simply go about their daily lives free from fear or arbitrary arrest,'' the letter read, adding that it's also "the target of protest and the source of new problems rather than a solution.''

Democratic Rep. Elijah Cummings said Sunday he will ask President Barack Obama and congressional leaders to send a bipartisan delegation "to look at what is going on in Baltimore.''

"It is so symbolic of what is going on all over this country. We have to address the problems of the urban areas because so many our young people are being left behind,'' Cummings said.

Associated Press writers Michael Biesecker and Juliet Linderman, and radio correspondent Julie Walker in Baltimore contributed to this report.