Arrest made in Nicholas Day killing

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MT. HOREB, Wis. (WMTV) -- Almost one month to the day since Nicholas Day was found dead on a county highway in Blue Mounds, the Dane County Sheriff’s Office has announced the arrest of the man accused of killing him.

Riley Berg

On Thursday, Riley Berg was taken into custody by Dane Co. Sheriff’s detectives and booked into the Dane County Jail on a single count of first-degree intentional homicide, Sheriff Dave Mahoney said Friday during a news conference.

“What we don’t know is why,” Mahoney added, noting that investigators have not found a connection between the 21-year-old Berg and Day, nor have they been able to determine a motive. As such, Dane County investigators will remain in the community to try to determine why the killing happened, Mahoney said.

WATCH: The Dane County Sheriff provides updates Friday:

He went on to urge anyone who may know how the pair were linked or knows of Berg’s activities or behavior around the time of the Jan.15 killing to call 608-284-6900.

For the first time Friday, Mahoney described some of the events that led to Day’s death, which the sheriff had long described as a “cold, calculated act.” According to Mahoney, Day was out for a jog when he was shot and then suffered multiple, significant cuts to his neck.

“Nicholas was a son, a loving father and a U.S. Veteran. This is a tragic event, that will live on for some time, especially for the two families whose lives have been torn apart,” said Sheriff Mahoney.


Day’s body was found along CTH JG, in Blue Mounds. His death was originally thought to be a hit-and-run, but the medical examiner later ruled his death was the “result of homicidal violence.”

Since that time, detectives have reviewed “a large amount of video” from the day of the killing and spoken to several witnesses, including a jogger who was believed to be in the area at the time. Most recently they reportedly spoke to a truck driver who was not a suspect, but they though may have relevant information.

READ: Blue Mounds man's death a "cold and calculated act," Dane Co. Sheriff says


People who knew Day described him as friendly, cheerful and hardworking. Brian McIntyre, Day’s former teacher and cross country coach at Mount Horeb High School, said Day loved to run.

“Even though he was a conference champion, he was extremely talented at running, he never just focused on himself. He was always cheering on other people,” McIntyre said.

McIntyre says after after Day graduated from high school, he joined the U.S. Navy. Day had left the Navy and had been back home for some time by January 2020.

McIntyre added that the route Day was running along on Jan. 15 was one of the routes the high school track team used to run as well. “It’s got to just break your heart,” McIntyre says.


At multiple times during the investigation, the Sheriff’s Office has put out public calls looking to identify potential witnesses. They have also announced a $1,000 reward for information leading to the killer’s arrest.

Anyone with information about Day’s killing is asked to contact authorities at (608) 284-6900 or the non-emergency dispatch number of (608) 255-2345. Madison Area Crime Stoppers is now offering a $1000 reward for information leading to an arrest. All callers can remain anonymous, they added.

Nicholas Day (Photo Courtesy: Ciara Day)