All six officers charged in the police-custody death of Freddie Gray were indicted by a grand jury, a prosecutor said Thursday.

The indictments were very similar to the charges Baltimore State's Attorney Marilyn Mosby announced about three weeks ago. The most serious charge for each officer, ranging from second-degree "depraved heart" murder to assault, still stood.

Gray suffered a critical spinal injury after police handcuffed, shackled and placed him head-first into a van, Mosby has said. His pleas for medical attention were repeatedly ignored, she said.

Mosby said prosecutors had presented evidence to the grand jury for the past two weeks. Some of the charges were changed based on new information, but she didn't say what that new information was. She also did not take questions.

"As is often the case, during an ongoing investigation, charges can and should be revised based upon the evidence," Mosby said.

In all, three of the officers had additional charges brought against them while three others had one less charge.

Gray was arrested April 12. He died in a hospital a week later and became a symbol of what protesters say was police brutality against blacks.

Two officers, Edward Nero and Garrett Miller, were indicted on second-degree assault, misconduct in office and reckless endangerment.

Caesar Goodson, who drove the transport van, faces manslaughter and second-degree "depraved heart" murder. Sgt. Alicia White, Lt. Brian Rice and officer William Porter are each charged with manslaughter, second-degree assault, misconduct in office and reckless endangerment.

Gray died on April 19, one week after he was critically injured, and his death inspired outrage among Baltimore residents that spawned protests that at least two points gave way to violence, looting and arson. In the wake of the riots, Democratic Mayor Stephanie Rawlings-Blake implemented a curfew for all Baltimore residents, and Republican Gov. Larry Hogan declared a state of emergency.

Gray was arrested in the Sandtown-Winchester neighborhood of West Baltimore. According to court documents, Gray made eye contact with a police officer and took off running. He was apprehended two blocks away and arrested for possession of what Miller wrote in charging documents is illegal under a city ordinance.

Mosby said the arrest was unlawful because the knife is legal under state law.

None of the officers secured Gray's seatbelt in the van, a violation of police policy. Soon after he was placed in the van, Goodson stopped to secure him with leg irons because he had become "irate," police said.

After a ride that included several more stops, including one to pick up a second passenger, the van arrived at the Western District station house. By that time, Gray was non-responsive.