David Lovrak of the Pierce County Law Enforcement Support Agency was told by his supervisor he must improve his handling of calls in the future, The Salt Lake Tribune reported Friday.
Lovrak was on duty in February when a social worker called 911 after being locked out of a supervised visit between Powell and his two sons at Powell's home in Graham, Wash.
Authorities said Lovrak asked the social worker unimportant questions and failed to grasp the situation.
When the social worker said she smelled gas, Lovrak assumed she was smelling the fumes of the car she left idling.
By the time help arrived 22 minutes later, police said Powell had attacked his children with a hatchet and set the house on fire, triggering an explosion.
Powell and his sons, Charlie, 7, and Braden, 5, died in the explosion.
At the time Powell was under suspicion in his wife Susan's 2009 disappearance and also involved in a bitter child custody dispute with her parents.
Lovrak is an 18-year veteran of the Law Enforcement Support Agency.