Reuters – A black man died in a Baltimore hospital on Sunday, a week after he was arrested and dragged into a police van by white patrol officers, authorities said on Sunday, raising questions about how he sustained his injuries and prompting an investigation.

Freddie Gray, 27, died at the Shock Trauma Center, a part of the University of Maryland Medical Center, hospital spokeswoman Karen Lancaster said.

He was brought to the hospital on April 12 after his arrest on suspicions of criminal activity, according to police, who have not revealed any specific allegations against him.

The hospital did not disclose the cause of Gray's death. Local media, citing a family spokesman, have reported that he had spinal injuries.

Representatives of the hospital and the Baltimore police were not immediately available for further comments.

Gray's death follows a series of killings of unarmed black men by white police officers. The deadly encounters, including incidents in Ferguson, Missouri, and New York City, have raised a national outcry over the treatment of minorities by law enforcement.

Most recently, a white officer in North Charleston, South Carolina, was charged with murder earlier this month after a bystander's video caught him shooting a black man in the back as he fled from a traffic stop.

In a televised news conference on Sunday, Baltimore Mayor Stephanie Rawlings-Blake extended her condolences to Gray's family and said city officials were asking questions about the incident.

"How was Mr. Gray injured?" Rawlings-Blake asked. "Were proper protocols and procedures followed?"

She promised that officials would get the answers to these questions through a prompt investigation.

Gray was suspected in criminal activity and arrested in a high-crime area, Baltimore police said.

A video taken by a civilian showed officers dragging Gray into the van, but did not show what happened afterward.

Baltimore Deputy Police Commissioner Jerry Rodriguez said at the Sunday news conference that police had no evidence of an altercation that would have resulted in the death.

While you were sleeping, this also happened...