BALTIMORE — Police were conducting a criminal investigation Sunday into the death of a man injured in their custody, and the mayor vowed to ensure the city held “the right people accountable.”

Freddie Gray, 25, of Baltimore, died Sunday at a hospital, a week after he was hurt following an arrest. A timeline released earlier in the week by police said Gray was taken by a van from the scene to a station, where an ambulance was called to treat him and take him to the University of Maryland R Adams Cowley Shock Trauma Center. Civilian video showed him being loaded into the van, but did not show the entire encounter.

An attorney retained by Gray’s family, Billy Murphy, described extensive injuries Sunday.

“What we know is that while in police custody for committing no crime, for which they had no justification for making an arrest except that there was a black man running, his spine was virtually severed, 80 percent severed in the neck area, and he died of those injuries,” Murphy said.

Mayor Stephanie Rawlings-Blake and top police officials promised accountability and transparency Sunday at a news conference at City Hall.

Deputy Commissioner Jerry Rodriguez said a criminal investigation was underway.

“It’s a two-part investigation. One is a criminal case, for Mr. Gray and also the officers. We always have that component in there to determine whether there is criminal culpability,” Rodriguez said.

Rodriguez declined to specify why four bicycle officers stopped Gray, who was in and out of prison for several drug convictions in Baltimore, starting in 2008, according to online court records. He had a trial scheduled May 21 on new drug charges stem- ming from an arrest in December.

“We had officers in a high-crime area known to have high narcotic incidents,” he said “The officers believe that Mr. Gray was immediately involved or recently involved in criminal activity and decided to make contact.”

Police have not released any video of the incident, including the civilian video shown on local news outlets. However, Rodriguez said the video did not reveal use of force by officers.