SIOUX FALLS, S.D. (KELO) — Just released court documents offer new information on the investigation into T. Denny Sanford.

A ruling from the South Dakota Supreme Court on April 6 allowed the search warrant affidavits to be unsealed.

Sanford was investigated for child pornography and was never charged. Sanford’s lawyers wanted the court to keep search warrants and other documents from the investigation sealed.

The documents show the investigation started in South Dakota in August 2019 when the National Center for Missing and Exploited Children sent a cyber tip to the South Dakota Internet Crimes Against Children Task Force. A tip had been submitted in July 9, 2019, regarding an AOL/Oath Inc. user account that contained image files that were suspected of depicting child pornography and child erotica.

The agent assigned to the case traced those images to an account used by Denny Sanford. The agent viewed three images of what appeared to be naked underage girls.

The investigation also led authorities to a phone registered to PREMIER Bank, which Sanford started. Someone at the bank confirmed the number was used by its founder.

Another affidavit says the agent also got access to an email address and found six more images of nude prepubescent girls sent by a Samsung Galaxy phone.

Investigators filed the affidavits to gather more information from Verizon and Midco to better determine whether Sanford had been the one to download the images.

Three months into the investigation by the South Dakota DCI agent, he says he was contacted by Attorney Marty Jackley who said he was representing Sanford and PREMIER Bank.  Jackley asked for all further communication go through him. Jackley is now the South Dakota Attorney General and his office released a statement regarding the case on Thursday.

In 2019, the Division of Criminal Investigation began investigating whether T. Denny Sanford had possessed child pornography. Search warrants were issued. That investigative file was then forwarded to the United States Attorney office in South Dakota, which forwarded it to the Department of Justice. The file was also forwarded to the authorities in Arizona and California. To date, none of those authorities have lodged charges against Sanford.

In 2022, after Attorney General Jason Ravnsborg was impeached and suspended, his administration issued a statement that it did not find probable cause for criminal charges in the state of South Dakota.

Tony Mangan, Communications Director

In January 2022, Jackley filed a 30-page document that included emails Jackley said are proof of hacking into Sanford’s accounts.

It’s a claim Sanford’s current lawyer, who represented him during the South Dakota Supreme Court hearing in March 2023, repeated in a statement from her client on Thursday.

Mr. Sanford appreciates that after a thorough investigation the authorities concluded there exists no prosecutable offense.  Here, because there is no prosecutable case or further action to be taken, the court records being released contain only allegations.  These preliminary allegations were provided to law enforcement prior to law enforcement’s exhaustive investigation and its realization that various individuals had documented access to the electronic devices at issue, including signs of hacking. While some claim releasing affidavits that reiterate these allegations constitute transparency, releasing preliminary allegations made prior to completing the full investigation only misinforms people and obscures the investigation’s conclusions that no prosecutable offense occurred.

Stacy Hegge

The documents released on Thursday were in a single file in the Minnehaha County Clerk of Court’s office. ProPublica and the Argus Leader filed requests to unseal the files. The State would not allow the documents to be unsealed until after the investigation was over but the state has filed notice its investigation is completed. 

Sanford is now 87 years old and had donated billions of dollars to philanthropic causes.