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(AP) — The mayor of Baltimore called the unexplained death of Freddie Gray unacceptable and demanded answers Friday to why police policies were not followed during his arrest.

“I want answers,” Mayor Stephanie Rawlings-Blake said at the end of a week of angry protests criticizing the police department. The mayor thanked the demonstrators for being peaceful.

She said the police commissioner assured her the investigation into Gray’s death is moving as quickly as possible and she expects the results to be turned over to prosecutors in a week. They will decide whether any criminal charges will be filed.

Gray was arrested April 12 after he made eye contact with officers and ran away, police said. Officers held him down, handcuffed him and loaded him into a police van. While inside, he became irate and leg cuffs were put on him, police have said.

Gray was not buckled with a seat belt, a violation of the police department’s policy.

He asked for medical help several times and after a 30-minute ride, paramedics were called. At some point — either during his arrest or inside the van — he suffered a mysterious spinal injury. Authorities have not explained how or when it occurred. Six officers have been suspended with pay during the investigation.

Gray was in the hospital for a week. He died Sunday.

The leader of a group of local ministers called Friday on Police Commissioner Anthony Batts to resign immediately.

“It seems that no one in the police department can explain what happened,” said the Rev. Alvin Gwynn Sr., president of the Interdenominational Ministerial Alliance of Baltimore.

He said the police department is “in disarray” and Batts has shown a “lack of viable leadership capabilities.”

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