Attorneys for St. Anthony, Minnesota, Police Officer Jeronimo Yanez, who fatally shot a black school cafeteria worker in a suburb of Minneapolis last year, have asked prosecutors to present any evidence their witnesses may be biased or unreliable.

The motion from Yanez’s three attorneys asked the Ramsey County District Court to order prosecutors to “disclose both evidence impeaching and favorable to the defense,” the Minneapolis Star Tribune reported Tuesday. Specifically, Yanez’s legal defense requested evidence indicating biases among the witnesses prosecutors were planning on using in the case. 

This involved the state’s disclosure of whether any of the witnesses were under the influence of narcotics during the time of their observations. The defense has argued in previous legal motions that Philando Castile, 32, the victim, had marijuana in his system at the time of the incident and was thus responsible for what transpired.

Read: Police Shootings By Race: Among People Shot By Officers, Blacks Twice As Likely To Be Unarmed As Whites, New Research Says

The motion presented to the court Tuesday also asked prosecutors to reveal any information regarding Castile’s previous criminal history, and if there were any charges against Castile at the time of the fatal shooting.

The racially charged July 6, 2016, killing drew national attention when Castile’s girlfriend live streamed its aftermath on Facebook. The Latino officer fatally shot Castile during a traffic stop for a broken taillight. Castile's girlfriend, Diamond Reynolds, and her 4-year-old daughter were in the vehicle with him. 

Defense attorneys say Yanez, 28, shot Castile seven-times in self-defense after he was told there was a legal gun inside the vehicle. Castile was reaching for his wallet, which held his state permit to carry a weapon, when he was shot.

Yanez turned himself in at the Ramsey Country jail the day after the shooting. He was charged Nov. 16, 2016, with one count of second-degree manslaughter and two counts of dangerous discharge of a firearm in the incident after large-scale protests by social justice groups like Black Lives Matter.

At least 968 Americans were killed by U.S. police officers in 2015, the Washington Post reported. Although black men represent 6 percent of the U.S. population, they made up 40 percent of those who were killed while unarmed that year. Black Americans were three times more likely to be killed by police than their white counterparts when adjusted for the populations where the shooting occurred.