Interesting to note:

The case marked the first murder prosecution of an on-duty Bay Area police officer. Prosecutors rarely file charges against police for shootings. A Chronicle review of police use-of-force cases around the country found just six cases in the past 15 years – not including the BART shooting – in which murder charges had been filed.

This either means police (and BART cops) in the Bay Area are (were) extremely careful about using lethal force or they’re in bed the the D.A.’s office.
From the Chron.