Baltimore Police Union
A copy of a letter from the police union local president Gene Ryan to Maryland State's Attorney Marilyn Mosby is pictured, May 1, 2015. Six Baltimore police officers have been charged, including one with murder, in the death of Freddie Gray, who was arrested and suffered fatal neck and back injuries while riding in a moving police van, the city's chief prosecutor said Friday. Reuters/Chris Helgren

Baltimore police officials are reportedly angry over the announcement of murder and manslaughter charges against some of the officers involved in the arrest of Freddie Gray, the 25-year-old black man who suffered fatal back and neck injuries while in the officers' custody, and whose death caused civil unrest and rioting in recent days. At a Friday press conference, Baltimore City State's Attorney Marilyn Mosby said the officers illegally arrested Gray and were negligent in getting him medical attention after his injury in the back of a police van.

An unidentified city police department source told a Fox News reporter that officers were "pissed" by the state's attorney's announcement. The police source also claimed that the medical examiner's office switched its ruling in Gray's death from accidental to homicide after meeting with the police officials.

Four of the six suspended police officers facing the more serious charges are: Officer Caesar Goodson Jr., 45, the driver of the police van, charged with second-degree murder, manslaughter, second-degree assault, two vehicular manslaughter charges and official misconduct; Officer William Porter, 25, involuntary manslaughter, second-degree assault and official misconduct; Lt. Brian Rice, 41, involuntary manslaughter, second-degree assault and official misconduct; and Sgt. Alicia White, 30, involuntary manslaughter, second-degree assault and misconduct in office.

Officers Edward Nero, 29, and Garrett Miller, 26, were not charged with murder or manslaughter. But both are facing second-degree assault and official misconduct chargers. Miller is also facing a false imprisonment charge.

The charges "are not an indictment of the entire police department," Mosby said in a press conference on Friday. She added that the officers' alleged actions "will not and should not damage" the relationship between the police and the community.

The Baltimore police officers' union defended the six officers charged in the Gray case, saying they weren't responsible for the Gray's death, the Associated Press reported. Fraternal Order of Police Lodge 3 President Gene Ryan made the following comments in a letter to Mosby, before she announced the charges:

"As tragic as this situation is, none of the officers involved are responsible for the death of Mr. Gray," Ryan wrote, while also calling for a special prosecutor to take over the case. "To the contrary, at all times, each of the officers diligently balanced their obligations to protect Mr. Gray and discharge their duties to protect the public." On Friday, Mosby said she would not hand over the case.