Six officers were charged after the April 2015 death of Gray, a 25-year-old who sustained a neck injury while in police custody. Three of them had already been acquitted.
A pretrial hearing for Officer Garrett Miller had been set for Wednesday. Trials for Officers Alicia White and William Porter had been scheduled for the fall.
Baltimore Chief Deputy State’s Attorney Michael Schatzow made the request to drop charges against them in court Wednesday.
Three officers were acquitted in the case: Edward Nero, a bike officer involved in the initial police encounter with Gray; Caesar Goodson, who drove the van that transported Gray; and Lt. Brian Rice, the highest-ranking officer charged in connection with Gray’s death.
A retrial against Porter had been scheduled after a jury deadlocked in the case against him in December.
The death of Gray, who was black, ignited a wave of protests as debate surged nationwide over whether police use excessive force, particularly against African-Americans.
The announcement that charges against the three officers would be dropped comes more than a year after Baltimore State’s Attorney Marilyn Mosby announced the officers would be charged. Her statements drew praise from some who admired how swiftly she took on the case, and criticism from others who said there wasn’t enough evidence to convict the officers.