Gray, a 25-year-old black man, died in police custody in April, sparking protests and riots in Baltimore. Six officers have been charged in his death, all of whom have pleaded not guilty.
In documents filed Thursday, the defense claims investigators from the Baltimore Police Department had information that Gray participated in "crash for cash" schemes, wherein he would intentionally injure himself to collect from insurance companies.
No proof was provided for that allegation. The document also claims Gray injured himself at the Baltimore City Detention Center so severely that he required medical attention. It was unclear when the alleged incident took place.
"When BPD investigators attempted to follow-up on this evidence of a pertinent character trait of Mr. Gray, they were told by Assistant State's Attorney Janice Bledsoe 'not do the defense attorneys' jobs for them' and to cease any further investigation into the matter," the filing read.
"The statement to investigators 'not do the defense attorneys' jobs for them' would seem to indicate some level of knowledge that exculpatory evidence exists which could benefit the officers charged in Mr. Gray's death and that the prosecutor did not want this information uncovered by investigators."
The document also described alleged efforts by prosecutors to set up private meetings with judicial officials and the medical examiner's office.
In response to the new filing, Baltimore City State's Attorney communications director Rochelle Ritchie would say only, "We will litigate this case in the courtroom."
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Attorneys for the Gray family did not immediately respond to a request for comment.
Thursday's filing comes after other filings in support of the defense's request for the office of Baltimore City State's Attorney Marilyn Mosby to recuse itself from the case.
Last week, attorneys argued in documents that Bledsoe had represented Gray in an unrelated 2012 criminal case, creating the potential for a conflict of interest.
The documents included a letter dated September 11, 2012, from the Office of the Public Defender addressed to Bledsoe, informing her that she had been assigned a case for Gray, who was being charged with possession of cocaine and marijuana with intent to distribute.
In addition to the alleged conflict of interest, the defense filed two other motions last week accusing Mosby's office of "judge shopping" for search warrants as well as engaging in a "systematic effort to intentionally withhold clearly discoverable evidence from the defense."
Bledsoe, who previously worked in the Baltimore City State's Attorney's Office in 2011 and 2012, stood alongside State's Attorney Mosby in May when she announced charges against the six officers in Gray's death.
They are as follows: Officer Garrett E. Miller, who joined the force in 2012; Lt. Brian W. Rice, an officer since 1997; Officer Edward M. Nero, on the job since 2012; Officer Caesar R. Goodson Jr., a veteran since 1999; Sgt. Alicia D. White, on the force since 2010; and Officer William G. Porter, who joined the force in 2012.