A trooper pursued an SUV that was speeding at 90 mph with Iowa Gov. Terry Branstad inside, but declined to pull the driver over after realizing he was transporting the state's top elected official, audio recordings released Tuesday indicate.

The Iowa Department of Public Safety said it has launched a review of its handling of the April incident in which dispatchers, according to the recordings released to The Associated Press, laughed after learning the vehicle in question was the governor's.

Days later, the department placed the investigator who initiated the pursuit, Special Agent in Charge Larry Hedlund, on administrative leave. Hedlund's attorney said Tuesday the personnel action was retaliation for the agent complaining to superiors that the trooper driving the governor was improperly given a pass after putting public safety at risk. A Branstad spokesman denied that allegation.