Randy Seiler, South Dakota Democratic Party chairman, died Monday, according to SDDP

Randy Seiler, the outgoing chair of the South Dakota Democratic Party, has died, a friend of the Seiler family and officials with the South Dakota Democratic Party confirmed Tuesday.

Seiler went into cardiac arrest on Thursday while running at Oahe Dam near Pierre. He had been in a medically-induced coma and was being treated at a Sioux Falls hospital.

He passed away late Monday night surrounded by family, according to the SDDP.

Seiler served as the U.S. Attorney for the District of South Dakota between 2015 and 2017. He'd spent 22 years working in the U.S Attorney's Office.

He ran for attorney general in 2018 but lost to former attorney general Jason Ravnsborg, who was later impeached in 2022 after fatally striking a man while driving.

Seiler grew up in Herreid, South Dakota, and served in the U.S. Air Force, including a tour in Vietnam. He graduated from the University of South Dakota School of Law.

He leaves behind his wife, Wanda, four children and grandchildren.

South Dakota Attorney General Marty Jackley posted a tribute on Facebook, calling Seiler "a brilliant lawyer, a great U.S. Attorney for SD, a strong advocate for victims, a dear friend, and most importantly, an amazing father and husband."

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Sen. Reynold Nesiba, D-Sioux Falls, and minority leader in the South Dakota Senate called Seiler's passing "an enormous loss to the people of SD."

U.S. Sen. Mike Rounds said on Twitter that Seiler wasn't just a neighbor, but a good friend.

"I always appreciated our candid conversations about issues facing South Dakota. He cared deeply for our state and our citizens," Rounds said. "Our neighborhood will not be the same without Randy."

Jennifer Slaight-Hansen, the acting chair of the SDDP, issued a statement Tuesday.

"I am in shock. We have lost one of the great leaders of our Party," Slaight-Hansen said. "I personally have lost a mentor and friend. I fall short of words to express my sadness on his sudden passing. I pray his soul rests in peace. I wish Wanda and his family immense strength as they move forward.”

Jamie Smith, who ran on the Democratic ticket for governor against Republican Gov. Kristi Noem in 2022 and was the former House Minority Leader, called Seiler a dear friend "whose profound impact on South Dakota cannot be understated."

This article originally appeared on Sioux Falls Argus Leader: Randy Seiler, chairman of SD Democratic Party, died Monday