Sgt. Tom Smith died Tuesday from a single bullet wound to the chest. It was fired by a fellow officer during a probation search in Dublin.
Sources close to the investigation told the Chronicle the shooting may be the result of a split-second misjudgment by officer Michael Maes.
The Alameda County Sheriffs' Office is investigating the shooting death.
Spokesman Sgt. J.D. Nelson told the Oakland Tribune that there are news reports that are painting an inaccurate picture of what happened, and that more information is needed before making any conclusions.