Riley Berg Arrested For Alleged Homicide

Authorities announced Friday that they believe they know who killed Nicholas Day. They know how. And when.

They just don’t know why. 

“At the hands of Riley Berg.” That’s how Dane County Sheriff Dave Mahoney answered a reporter’s question about how Day died. The victim was found shot and with multiple lacerations to his neck on a rural road in the Town of Blue Mounds on January 15. 

On Thursday evening last week, authorities took Berg, 21, of Mount Horeb, into custody. He was booked into Dane County Jail on a tentative charge of First Degree Intentional Homicide. 

The following day, on Valentine’s Day at the Mount Horeb Public Safety Building that has served as a command post for the investigation for the past month, Mahoney stood with officers from the Mount Horeb and Blue Mounds police forces, along with the case’s two lead investigators with the Dane County Sheriff’s Office, to announce the arrest. But while they believe they have the killer in custody, they say many questions are still unanswered. 

His initial court appearance took place Monday. The judge set a cash bond of $1 million.

Mahoney said the killing was “cold, calculated and extremely violent.”

“What we don’t know is why,” he continued, adding: “We have found no known connection between Nicholas Day and Riley Berg.”

He urged anyone with information about Day or Berg to call the Dane County tip line at 608-284-6900.

“Please contact us,” he urged, adding, “It’s crucial.”

“Nick Day was a son, a loving father, and a U.S. veteran,” said Mahoney. 

“While out for a run in beautiful Dane County, Nick Day was shot, and then suffered multiple significant cuts to his neck, leading to his death. We know that this attack occurred over a very short window of time,” he continued. “But what we don’t know, is why.”

“Riley Berg’s motives for this homicide are still unclear,” he said. 

He said Mount Horeb and Blue Mounds are “one of Dane County’s gems, and people live here because these types of crimes don’t happen, not very often anyway.”

While he would not give details about how they cracked the case, Mahoney said it was done with hard investigative work, good instincts and “tenacity.” 

“It is tragic in many ways and I know it will take a long time to heal,” he said.

Monday’s court appearance suggested that a timeline, video footage and DNA linked Berg to the crime. 

Shortly after Day’s death, one of his closest friends, Trevor Hook, stated: “Just to think that somebody wanted to kill him is unbelievable to me. Maybe they had the wrong person, because I just can’t imagine it. He never made anyone mad.”  

When Hook learned Berg had been arrested for the crime a month later, he had mixed emotions. 

“As much joy as a feel I should have gotten from this, it sort of opened up a whole other can of worms,” he said. “Yes, they got him. But we just want to know why.”

“It definitely helps to know they at least caught him,” he continued. “If an answer never comes out, I guess we’ll just have to live with it.”

Whether those answers will ever come remains unclear. 

“We will be remaining in Mount Horeb and need details from anyone who knows Riley, such as his activities before and after this homicide,” Mahoney said. “Anyone with information, no matter how small you think it might be, please contact us.”

“Even though we have made an arrest, we continue to need your help,” the sheriff added. 

The Dane County Sheriff’s Office on Wednesday, Jan. 15 said it was investigating a vehicle versus pedestrian crash resulting in the death of an unidentified Blue Mounds man. “The preliminary investigation indicated the victim was running southbound towards Mt. Horeb on County Highway JG just south of Bergum Road in the Town of Blue Mounds when he was struck by an unknown vehicle,” said a press release sent out by the DCSO public information officer. “Based on witnesses who reported seeing the victim running in the area, it is believed the incident occurred sometime between 12:45 p.m. and 1:15 p.m. on Wednesday, January 15.”

His body was discovered in the 3100 block of Highway JG. While rumors were rampant in the community, he was not decapitated. 

Preliminary autopsy results by the Dane County Medical Examiner the following day showed the victim, at that point identified as Day, had died from “homicidal violence” and not in an accident.

County investigators sought the public’s assistance, going door-to-door in Mount Horeb and Blue Mounds, scouring the communities for leads and checking for any camera footage that might tell them exactly when and where he was running prior to his death. In the days and weeks that followed, the sight of sheriff’s deputies going door-to-door became a common sight in the village and the town. 

“It’s been a traumatic, traumatic [month],” the sheriff said. He went on to acknowledge that Day’s mysterious death caused sorrow and concerns about safety in the community. He also said he is aware that investigators “disrupted your lives” while searching for leads. “It was what was required to do, to get us to this point,” he stated. “We’ve knocked on your doors. We’ve endlessly asked you a lot of questions, many of which we know have raised concerns about your safety. We understand that. We are concerned about that. We worked closely with the Mount Horeb and Blue Mounds police departments, to make sure the community was safe – as safe as we could make it with the information we had.”

Court records indicate Berg had been diagnosed with schizophrenia, and had been hospitalized for the condition in 2017. That same year, Berg was pulled over for speeding by a Mineral Point police officer. That officer said Berg first refused to give his name, then gave an alias of “John Riley,” alleging: “You are violating my rights.” Berg then rolled up his window and refused to open it when additional law enforcement arrived. He was arrested and booked for obstruction. 

After announcing that Berg was arrested for allegedly killing Day, Mahoney thanked the Mount Horeb Fire Department for its assistance and the use of its space for a command post, as well.

“This tragedy will live on here for a long time,” stated Mahoney. “It has specifically torn apart many families, and I call upon our community to offer compassion and help.”

Several people in Mount Horeb, speaking under the condition of anonymity, said they had only fond memories of Berg. They remembered him as a local high school student who worked hard and lifted weights. They spoke fondly of his parents and siblings. They spoke of their shock, and their sadness when they learned of the alleged crime.

As one young woman walked out of the public safety building last week, surrounded by friends, she made perhaps the quintessential statement about the case, for those who live in this small, relatively safe community. 

“I knew him,” she said of the victim. Of the alleged killer she added: “I knew him, too.”