The mayor of Baltimore said Friday she wants answers to why police policies were not followed in the unexplained police-custody death of Freddie Gray.

Mayor Stephanie Rawlings-Blake told reporters that the police commissioner has assured her the investigation into Gray's death is moving as quickly as possible. She said results are expected to be turned over to prosecutors in a week.

"This is a horribly tragic incident and I'm determined to get to the bottom of it," Rawlings-Blake said during a press conference Friday. "I know that this is absolutely unacceptable and I want answers."

"I still want to know why none of the officers called for immediate medical assistance despite Mr. Gray’s pleas," she said. 

Gray was arrested April 12 and loaded into a police van. At some pint, he suffered a mysterious spinal injury. He died Sunday.

Local and federal authorities are investigating the death. Six officers have been suspended with pay.

The arrest and death have sparked marches and rallies by demonstrators who say police mistreat black in Baltimore and across the country.

"If necessary, we will hold the appropriate parties responsible," the mayor said. She asked the public to remain patient as a thorough investigation is conducted. 

"In order for us to have justice and not just seek justice, we have to follow the process," she said. 

A wake will be held Sunday for Gray. The funeral is set for 11 a.m. Monday at New Shiloh Baptist Church.

The Rev. Harold Carter Jr. will preside at the service and the Rev. Jamal Harrison Bryant will deliver the eulogy.

FoxNews.com's Cristina Corbin and The Associated Press contributed to this report.