The move came in the same day that he was formally charged in federal court, according to a media release from the U.S. Attorney's office.
U.S. Attorney Tim Morrison said Alexander still must formally plead in federal court and he can withdraw the motion and decide not to plead guilty at any time, as well.
Morrison would not comment whether Alexander's motion was a result of a deal the prosecutor's office struck with the former Greencastle resident.
Alexander faces at maximum of 10 years in prison and a $250,000 fine, but Morrison declined to say what his sentencing recommendation would be if Alexander pleads guilty.
Alexander was originally arrested in May 2007 after an Indiana State Police investigation found that he had stolen about $45,000 in federal grant money from the Putnam County Sheriff's Dept. When charges against him were announced, he fled the county and was arrested days later at a Rockville campground.
While he was on the run, Alexander called the BannerGraphic and told an editor that he was following the orders of Sheriff's Mark Frisbie when he stole the money. Frisbie has denied that allegation.
The complaint filed in federal court against Alexander alleges that he applied for two separate federal grants for tactical gear for the sheriff's department, forged Putnam County Commissioner Gene Beck's signature on the receipt and then used an un-monitored sheriff's department bank account to funnel the cash into his private account.
Morrison said these are the only charges he expects to file against Alexander. However, he said the investigation is still ongoing.
State Police Sgt. Scott Stockton, who took the lead on the investigation of Alexander and later on the sheriff's department, said he is in the final stages of his investigation.
In its 2007 audit of Putnam County, the State Board of Accounts said the sheriff's department failed to establish internal controls that would have prevented Alexander's alleged theft. It called the department's oversight of federal grant disbursement "inadequate," as well.
Frisbie said he is awaiting federal action on the account that Alexander used before he closes it down. However, all future federal grants will be deposited in an account that is overseen by the Auditor and Treasurer, he said.
The account Alexander used predates his term as sheriff, Frisbie added.
In August, the Putnam County Council voted to approve an ordinance that would require any county department to receive its approval before opening a new bank account.
Alexander also faces three theft charges and a perjury charge, all felonies, in Putnam County courts.