Americans took to the streets outside the Baltimore police station to protest against the police killing of yet another black man.

Americans took to the streets outside the Baltimore police station to protest against the police killing of yet another black man.

Freddie Gray, a Baltimore man injured during an arrest by Baltimore police last week, died Sunday at Shock Trauma, prompting protests by city residents and out-of-town activists and promises from city officials for a thorough investigation.

Gray, 25, died a week after he suffered a broken vertabra after being arrested near Gilmor Homes in Sandtown-Winchester.

Police have not given a cause for Gray's injuries or specified why he was arrested, citing an investigation into the incident. Officials are expected to look into any criminal conduct by Gray and whether criminal charges against officers are warranted.

According to the lawyer, Gray's "spine was 80 percent severed at his neck" who also said based on autopsy results released Monday, Gray "did suffer a significant spinal injury that led to his death."

"What we don't know is how he suffered that injury," Murphy said.

Authorities do not have any videos or evidence that can explain what happened to cause the "medical emergency."

Police Commissioner Anthony Batts said that Gray, several times, asked for medical attention, including an inhaler, during his transport for medical care.

"There were several times he made a medical request," Batts said. "He asked for an inhaler, and at one or two of the stops it was noticed that he was having trouble breathing and we probably should have asked for paramedics."

The fresh protests were held amidst frustration over US police brutality against African-Americans which sparked massive demonstrations after African-American teenager Michael Brown was fatally shot by a white police officer in Ferguson last year.

The 18-year-old was shot to death in August 2014 by former police officer Darren Wilson who later walked free.