The attorney general's office has opened investigations into the 47 people killed. According to their own investigations, only 13 of these deaths appear to be related to the protests. They have said publicly that they have evidence identifying the specific police officer involved in three cases. So far, two police officers have been arrested. Of course, we would hope for much more, given that there are videos showing specific cases where protestors were killed.
On May 11th, 2021. See this statement in context.