Court documents reveal Blue Mounds homicide suspect has history of mental illness

Riley Berg's mugshot
Riley Berg
Dane County Sheriff's Office

MADISON, Wis. — Riley Berg, 21, will have his initial appearance in a Dane County courtroom Monday.

He was arrested Thursday night and will face a first-degree intentional homicide charge for the death of Nicholas Day.

Court records show that Berg was pulled over in Iowa County for speeding in 2017, resulting in him being arrested for obstructing an officer because he refused to tell the officer his full name.

According to the criminal complaint, the Mineral Point police officer who pulled Berg over spoke to Berg’s father days after the arrest. His father apologized for how Berg acted and told the officer that Berg was diagnosed with schizophrenia and was not taking his medication.

He said Berg was hospitalized earlier that year.

Berg has received four speeding violations in the last five years, along with a ticket for driving the wrong way on a one-way street and disorderly conduct. He has no criminal record.

During a news conference announcing Berg’s arrest on Friday, Dane County Sheriff Dave Mahoney called Day’s killing a “cold, calculated and extremely violent” homicide.

The incident was initially reported as a hit-and-run, but an autopsy confirmed Day’s death was a homicide. Day was shot while he was out for a run and suffered multiple “significant” cuts to his neck.

Mahoney said “the motive for the killing is still unclear, and at this point, a connection between the victim and the suspect is unknown.”