Allow me to clarify: the officer made a split second decision that the man represented a immediate (italicised for emphasis) capital threat to him and his colleagues, thus justifying the use of lethal force, and evidently his colleagues thought similarly.
Subsequent investigation has shown that the conclusion he drew was wrong, and a human being that didn't present an immediate capital threat was killed.
As per above, usually in situations where a human life has been taken without that justification being proven, there has to be some accountability rather than writing off a human life - criminal as it was - as "collateral damage" or somesuch.
So, to answer, no, I don't think he did the wrong thing given the information at the time and I don't think he should be punished, but at the same time I'm not entirely at home with the idea of the unaccountable death of a person who had not committed a capital crime or had been proven to present an immediate capital threat to law enforcement. That's not a nice road to go down.