Three of the Baltimore police officers charged in the death of Freddie Gray have argued in court filings that they gave initial statements under duress because they were afraid of being fired.

The Baltimore Sun reports that the attorneys for half of the officers charged with manslaughter made those arguments in motions filed this week.

Gray's death followed a neck injury he suffered in police custody in April, and the incident provoked widespread protests in the city.

What had been largely peaceful protests turned violent a week after the death during Gray's funeral, with the National Guard called in to restore order.

The Justice Department has opened a civil rights investigation into Baltimore police practices.

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Three of the six Baltimore police officers charged in the death of Freddie Gray have said their original statements to commanding officers were made under duress. Top row from left, Caesar Goodson Jr, Garrett Miller and Edward Nero, and bottom row from left, William Porter, Brian Rice and Alicia White

Baltimore State's Attorney Marilyn Mosby (right) charged the six officers with manslaughter - and Goodson with second-degree depraved-heart murder - after Freddie Gray went into a coma and died a week after his arrest

Two of the officers, Lt. Brian W. Rice, Officer William G. Porter, claimed in their motions they thought they were being interviewed as witnesses rather than suspects in Gray's death, according to the Baltimore Sun.

Their attorneys are asking for those statements to be thrown out.

Another, Sgt. Alicia D. White, claims that she was not read her Miranda rights before giving a statement, and was later called back to give a second account after being read the legal protections.

Her lawyer says that the second statement can also not be admitted because it was tainted by the first.

Two other officers, Officer Garrett E. Miller and Officer Edward M. Nero, made similar filings earlier in the case.

Officers have said that they were afraid of losing their jobs while making statements to surperiors in the aftermath of the arrest. From left, officers Goodson, Miller, Nero and Rice put Gray into the back of a police van

Gray's death sparked a wave of protests that were at first peaceful but then turned violent the day of his funeral. Above, a protester throws a liquor bottle at police lines on April 27

Five of the police officers being charged, all except Officer Caesar R. Goodson Jr, said they would like to be tried separately rather than as groups.

Baltimore State's Attorney Marilyn Mosby's charging the officers was seen as a bold move following several incidents throughout the country in which police had been involved in black men's deaths but not faced charges.

Freddie Gray, who was found to have a severely damaged spine, died a week after his arrest after going into a coma.

Through the 25-year-old was standing in an area known as a drug hotspot, many believe that the officers who tried to stop him had no reason for doing so.

He was then arrested for possession of a switchblade knife.

Gray's death was one of a string of incidents that got national attention after black man died in encounters with police

He was later seen screaming as he was taken into a police van, and continued to do so as additional shackles were placed on him during a stop in the ride.

Goodson has been charged with second-degree depraved-heart murder, which involves 'extreme indifference' towards harm of another person.

The officer, who is black, previously told Daily Mail Online that he is 'distraught' at Gray's death and is haunted by images of the unresponsive man.