(CNN) -- Federal investigators have cleared controversial Arizona sheriff Joe Arpaio's office of criminal wrongdoing regarding allegations of financial improprieties.
The U.S. Attorney's Office in Arizona declined to file charges against the Maricopa County Sheriff's office after an investigation into claims of abuse of county credit cards, misuse of funds and other financial matters.
The investigation is separate from a federal civil rights lawsuit accusing Arpaio's office of racial profiling.
The federal financial probe stems from a 2010 request from Maricopa County officials for help in investigating the claims of misuse of county funds. Federal authorities acted as "special deputy county attorneys" tasked with finding possible state charges.
Last year, federal investigators declined to press charges on several of the allegations. In a letter to the Maricopa County officials Friday, the U.S. Attorney's Office announced it will not initiate charges on two remaining claims.
"I am very happy with that," Arpaio said at a news conference.
Federal investigators "cleared my office of any abuse of power or wrongdoing that has been going on for years, and publicized almost every week for three years by the news media and critics," he said.
Arpaio, who calls himself "America's toughest sheriff," has long been a controversial figure for his tough, proactive stance against illegal immigration. But critics say his methods have created a system of racial profiling.
The sheriff is on trial stemming from a 2007 class-action lawsuit that alleges that his office "launched a series of massive so-called 'crime suppression sweeps' that show a law enforcement agency operating well beyond the bounds of the law."
The U.S. Justice Department has also filed a separate civil rights lawsuit against him.
But the allegations that were dismissed by the federal investigators were of a smaller scale.
One of the allegations was that the sheriff's office misused county credit cards. The feds found that the office was not properly documenting credit card transactions, but found no evidence of stealing county funds.
Another allegation was that the sheriff's office used funds earmarked for a program to pay the salaries of officers working on other projects. Investigators concluded that while the funds indeed where shifted from one law enforcement program to another, there was no "criminal intent."
Critics of Arpaio were displeased with the decision not to press charges, saying the sheriff clearly abused his power.
"It is a miscarriage of justice," Pablo Alvarado, director of the National Day Laborer Organizing Network said in a statement.
Arpaio said that if he had done something wrong, the federal government wouldn't have hesitated to bring indictments.
"I know my people do the right thing, they have a tough job, and because I'm a high-profile guy, sometimes there's more interest given to what we do," he said.