But UC Berkeley Boalt Hall Law School professor Franklin Zimring, a criminal justice expert, said "absolutely conclusive" videos of the shooting have convinced him there's no possible justification for Mehserle's actions.
"It's accident versus intention, but justification is off the table."
Whether Mehserle meant to draw his Taser but accidentally drew his firearm, or whether he meant to draw his sidearm but didn't mean to fire it, it looks like involuntary manslaughter, Zimring said.
In the absence of a statement from Mehserle, the proper thing to do is to charge the case based on the evidence at hand and then hear his side of the story later, Zimring said.
Anyone who was not a police officer would be in custody already.
