Oakland and BART police officers shot and killed a man Saturday morning near the Fruitvale BART Station... An Oakland officer fired his Taser at the man..., but he kept running... Oakland police again unsuccessfully tried to subdue him with a stun gun... That's when the man charged an officer, whose colleagues opened fire.[LINK]
If this report is reasonably accurate, then the police involved in this incident made only one error - relying on their tasers. They tried to use their tasers TWICE and neither time were they effective (for whatever reasons). The situation escalated until the man reportedly charged the police - he was reportedly armed with knives. At that point, the police (several of them?) opened fire killing the man.
It's not clear that the attempted and failed taser deployments actually increased the man's chances, or if reliance on the unreliable tasers actually led to an ever-increasing spiral.
At the very least, it's clear that two unsuccessful deployments in sequence and a man killed should be recorded as a DOUBLE FAIL for the taser.
UPDATE: See also Fred Collins, 48, dies in a hail of police bullets, after taser gun fails [LINK] for other reports that do not align with original police story.