In September 2010, a 63-page internal memo written by Maricopa Deputy Chief Frank Munnell, was made public.
The memo alleged years of misconduct and mismanagement by Arpaio's second-in-command and other top MCSO officers, including the use of a public-corruption task force to conduct politically motivated probes into political opponents.
The memo alleged that top officials in the MCSO "willfully and intentionally committed criminal acts by attempting to obstruct justice, tamper with witnesses, and destroy evidence."
Arpaio forwarded the memo to the Pinal County Sheriff's Office, requesting they conduct an administrative investigation.
Former top MCSO staffers claimed that Arpaio knew of the acts alleged in the Munnell memo, but took no action to stop them.
Arpaio has not commented publicly on the allegations.

In October 2010, the U.S. Attorney for Arizona confirmed that the FBI and Department of Justice had received copies of the Munnell memo and were conducting criminal investigations into its allegations.
In September 2010, a 63-page internal memo written by Maricopa Deputy Chief Frank Munnell, was made public. The memo alleged years of misconduct and mismanagement by Arpaio's second-in-command and other top MCSO officers, including the use of a public-corruption task force to conduct politically motivated probes into political opponents. The memo alleged that top officials in the MCSO "willfully and intentionally committed criminal acts by attempting to obstruct justice, tamper with witnesses, and destroy evidence." Arpaio forwarded the memo to the Pinal County Sheriff's Office, requesting they conduct an administrative investigation. Former top MCSO staffers claimed that Arpaio knew of the acts alleged in the Munnell memo, but took no action to stop them. Arpaio has not commented publicly on the allegations.
In October 2010, the U.S. Attorney for Arizona confirmed that the FBI and Department of Justice had received copies of the Munnell memo and were conducting criminal investigations into its allegations.
Joe Arpaio