Arizona Attorney General Mark Brnovich said he is walling himself off from an investigation connected to the activities of a major campaign supporter.

The attorney general's office is investigating a whistleblower's allegation that a state regulator who oversaw APS at the Arizona Corporation Commission was too cozy with the power company.

Brnovich, a Republican, benefited in last fall's elections from $425,000 that APS' parent company donated to a group targeting his Democratic opponent, Felecia Rotellini.

Capitol insiders have questioned whether Brnovich should farm the case out to another prosecutor.

In a statement Wednesday, Brnovich said the case presented no legal conflict, but he would still recuse himself:

"I do not have a legal conflict requiring disqualification of the Arizona Attorney General's Office in the recent Corporation Commission whistleblower case transmitted to my office. However, as Attorney General, I value the public trust and I would not want my participation to become a distraction.

"For these reasons, I have recused myself from any involvement in the investigation of the recent disclosures concerning alleged improprieties involving commissioners and staff at the Arizona Corporation Commission. Therefore, I have assigned Donald Conrad, the head of the Criminal Division, and John Lopez, Arizona Solicitor General, to conduct this investigation.

"Donald Conrad is one of our most experienced lawyers and formerly served as Terry Goddard's head of the Criminal Division. John Lopez is one of the most respected prosecutors in Arizona, formerly serving as the Executive Assistant U.S. Attorney. Under their direction, the people of Arizona can be confident that this investigation will move forward with an appropriate focus and professionalism that is beyond reproach."