"DOJ considers the oversight of an independent monitor to be an absolute necessity for meaningful and sustainable reform of MCSO," Austin wrote. "It was disappointing, to say the least, for you to contact us 24 hours before our negotiations were scheduled to continue and raise, for the first time, a precondition that you understood would result in the cancellation of negotiations -- and, by extension, the initiation of a civil lawsuit -- and calls into question whether you were ever interested in settling this matter."
Arpaio's office came under federal scrutiny back in 2008 and DOJ announced the findings of their investigation back in December. Officials found that Arpaio had "promoted a culture of bias" and his officers had discriminated against Latinos.
While he initially dismissed the findings of DOJ's investigation as a "sneak attack" intended to help President Barack Obama's reelection bid, Arpaio later claimed to be working with DOJ to settle the matter.
Now, Justice Department officials "believe that you are wasting time and not negotiating in good faith," Austin wrote. "Your tactics have required DOJ to squander valuable time and resources."
Sgt. Brandon Jones of the Maricopa County Sheriff's Office told TPM that Arpaio "has been given an ultimatum by the federal government and stands firm that he will not surrender his authority in the form of a federal monitor as he has always said."
Late update: Arpaio's full response is here.
Read DOJ's full letter below.
Additional reporting by Nick Martin.