Attorneys for Caesar Goodson, one of six officers facing criminal charges stemming from the death of Freddie Gray, filed two internal police documents that claim Gray complained of a back injury to police officers more than a month before his death in the back of a police van and he had a history of hurting himself while in custody.

The incident, first disclosed to defense attorneys during the trial for William Porter that ended in a mistrial earlier this month, is detailed in a police document that was until recently under seal. In the May 1 document, Baltimore Police Sgt. John Herzog says that during a March 31 meeting with Gray at the Western District station house, Gray "was awkwardly sitting in the chair, leaning to the left." Herzog wrote that when he asked Gray about his position, he responded "something to the effect of 'I hurt my back' or 'I have a bad back.'"

Herzog went on to write that the incident had slipped his mind but his memory was "jogged" after "rumors and information was released that Freddie Gray possibly had been involved in a car accident." Herzog said Gray had come to the station to provide information about a string of robberies in the neighborhood.

Goodson and five other officers were indicted May 1.

A second report from the police was also included in the filing: an anonymous tip, delivered to the department by phone May 22, from a woman who said Gray once injured himself and had to be restrained and disciplined while in a Baltimore jail. Defense attorneys have argued that Gray was banging in the back of the van during several of the six stops the van made on its 45-minute ride from the site of his arrest to the Western District station house, where he arrived unresponsive.

Prosecutors have said Gray's injuries stemmed from the negligence of the officers tasked with protecting him while he was in custody.

Goodson's trial is scheduled to begin Jan. 11. Goodson drove the transport van, and in addition to manslaughter, assault, reckless endangerment and misconduct in office charges, he faces the most serious charge: second-degree "depraved-heart" murder.

The filing also lists dozens of witnesses Goodson's attorneys could call to the witness stand. Among them are police officers, reporters, the former police commissioner and the state medical examiner. Many of those on the list testified during Porter's trial.