The union representing state troopers has backed off allegations that a drug investigation of Sherry Johnston was slowed down last fall to shield the national candidacy of Gov. Sarah Palin.

An inquiry Monday by officials for the Public Safety Employees Association concluded that investigators did not delay a search warrant for political reasons, said union president Rob Cox. Charges of political meddling erupted last week because of misunderstandings between investigators working on the case and senior state public safety officials, Cox said.

The drug-selling case against Johnston — whose son, Levi, is the father of Palin’s new grandson, Tripp — did draw unusual scrutiny from top public safety officials, Cox said. He said union and state officials hope to meet Tuesday to sort out any misunderstandings and determine whether political considerations had any effect at all.

Public Safety Commissioner Joe Masters issued a statement late Monday, repeating his assertion that the governor’s office was never clued in to the drug investigation and that trooper leaders were only trying to assure that the case was handled like any other.

“Events nationally, and their affects (sic) locally, certainly may have influenced Ms. Johnston’s behaviors and ultimately the timeline of the case,” Masters said. “However, the accusations that political motives were behind the decision on how to manage this case are baseless.