Arizona Corporation Commissioner Bob Burns subpoenaed Arizona Public Service, the state's largest utility, Thursday seeking access to documents related to alleged dark money that flowed to two commission candidates in the 2014 election cycle.
"For nearly two years now, APS has refused to voluntarily answer my questions about any political expenditures that APS/Pinnacle West may have made," Burns says in the subpoena's cover letter. "I now seek to continue my investigation to determine whether APS has used ratepayer funds for political, charitable or other expenditures."
The FBI is in the midst of a "long-term" investigation, dating back to June, related to financing in the 2014 election.
“We have received the subpoena from Commissioner Burns and we are reviewing it," APS said in a statement.
Burns is seeking reelection to the commission in Tuesday's primary.
He's up against fellow Republicans Rick Gray, Al Melvin, Andy Tobin and Boyd Dunn. There are three open seats on the commission.