bart cop up on murder...

... and has a history:

Following Tuesday's arrest of former Bay Area Rapid Transit officer Johannes Mehserle for murder in the fatal shooting of a defenseless suspect on New Year's Eve, another man has come forward to allege that Mehserle used excessive force against him on an earlier occasion.

Admittedly this dude is an extreme case, but it'd be nice if we could vet candidate cops like they were cabinet nominees. Too often, it seems, the uniform itself confers some sense of absolute authority -- absolute in the mind of the wearer anyway, nearly always exceeding that which is necessary. And when that happens, bad things, as most certainly in this case, occur.