PHOENIX -- A high-profile county sheriff says Arizona Attorney General Terry Goddard isn't cooperating with his investigation into possible corruption involving the AG's office. Maricopa County Sheriff Joseph M. Arpaio accused Goddard of interfering with an official investigation by hindering his contact with possible interviewees. Arpaio has been dubbed "America's Toughest Sheriff" on some cable-TV channels. He is probing a plea deal Goddard, a Democrat, reached with disgraced former state Treasurer David Peterson, a Republican, last December, LNL reported in April. Peterson admitted a misdemeanor and paid $4,200 after facing several felony charges. The sheriff said Goddard's attorney, Ed Novak, acts as the AG's "guard at the gate," the Wickenburg Sun reported, requiring notice for all contact with current or former employees. "Law enforcement officials must have unfettered access to witnesses and suspects," Arpaio said. "Mr. Goddard and Novak are getting in the way of that, which is tantamount to interfering with an official investigation." Peterson's punishment was widely considered a "slap on the wrist" at the time considering the other charges against him, the Arizona Capitol Times reported. They included fraud, forgery, misappropriation of public funds and a campaign-finance violation. Arpaio is currently probing whether payments last June of $1.9 million from the Treasury to the AG influenced Goddard's later treatment of Peterson. The payments were officially for the attorney general's efforts to win Treasury $5.2 million in a controversial fraud case. But the sheriff is clearly unhappy with Goddard's lawyer and his stalling on the investigation. "Stop hindering my deputies from investigating this alleged crime, and let's get this investigation over with," Arpaio exhorted the AG. Peterson became Arizona Treasurer in 2002 after defeating the Republican Party's favored candidate, Richard Petrenka, in the primary. He later defeated Democrat Ruth Solomon in the general election.