Prosecutors have asked a Baltimore judge to try an officer first in the Freddie Gray case because they say the officer will be called as a witness to testify against at least two other members of the force.

Deputy State's Attorney Michael Schatzow asked Judge Barry Williams in a letter earlier this week to schedule Officer William Porter's trial first because he is "a necessary and material witness in the cases against" Officer Caesar Goodson and Sgt. Alicia White.

Officers Edward Nero and Garrett Miller, and Lt. Brian Rice are also facing criminal charges in the case. Each will be tried separately.

The state also offered an alternative order, but didn't say why.

Gray died after suffering a critical spinal injury while in police custody.