Police say Nicholas Grundman admitted lighting fuel in a garage but denied trying to kill his wife.
GREENVILLE, Wis. — Investigators say gasoline poured near a refrigerator and workbench inside an attached garage helped turn a Greenville house fire into an attempted homicide case against a woman’s estranged husband.
The criminal complaint against Nicholas Grundman, 47, lays out a case built around fire origin, alleged admissions, a divorce filing and repeated contact before the blaze. Grundman is accused of setting the March 19 fire while his wife slept inside the Fawn Ridge Court home. He faces attempted first-degree intentional homicide, two arson counts, stalking, criminal damage to property and carrying a concealed weapon.
Police said the physical evidence at the garage scene raised concern early. Investigators reported finding signs of accelerant and a bottle of lighter fluid after firefighters responded shortly after midnight. The fire was inside a garage attached to the home, not a detached structure. That detail matters in the complaint because smoke moved into the house where the woman was sleeping. She woke only after one of her cats pawed at her face, then saw smoke spreading through the home. She told police, “Within seconds, my house was full of smoke.”
The woman escaped with three cats and two dogs. She also used a fire extinguisher to knock down the flames after finding the fire in the garage. No injuries were reported, but the complaint says her car was damaged and personal items belonging to her son were harmed. The fire response included the Village of Greenville Fire Department, the Outagamie County Sheriff’s Office and the Wisconsin Department of Justice Division of Criminal Investigation. Officials said their investigation found suspicious circumstances and led them to believe the blaze was not accidental.
The complaint later turned from the scene to Grundman’s own words. After his March 31 arrest at a construction site, police questioned him about the fire and his movements. He first said he was not “technically” at the home, while also saying he had been “being stupid.” He told investigators he often drove past the house to see whether his wife was seeing someone. He described the night before the fire as one of his “driving around days” and said he had been drinking heavily.
Investigators said Grundman eventually admitted he still had access to the garage and had entered it that night. The complaint says he told police he used gasoline from a red container on a shelf. He said he put some near the refrigerator, poured more on the right side of the refrigerator and placed gasoline on a workbench along the wall. Police said he then told them he lit the gasoline with a lighter. He told investigators he was remorseful and felt terrible, but he denied trying to kill his wife.
That denial is likely to be a central issue as the case moves through court. Prosecutors charged attempted first-degree intentional homicide, which focuses on intent, not only the act of setting a fire. The state’s theory is tied to the location of the fire, the timing, the woman’s presence inside the home and the alleged conduct before the blaze. Defense arguments have not been fully presented in public reports. Grundman has been ordered to stand trial after an officer testified at a preliminary hearing in April.
The alleged motive described by police centers on the collapse of the marriage. The woman filed for divorce in February after about a year and a half of marriage. She told investigators that Grundman’s drinking and job problems strained the relationship. In January, she said, she came home to find him intoxicated and newly unemployed, then told him to leave. She said she paid for him to stay in a hotel and later an Airbnb. By mid-March, she told police, she no longer knew where he was staying.
The complaint says Grundman’s contact with the woman escalated after the separation. She reported frequent calls and texts that came almost every 30 minutes through the night. On the day of the fire, she called him and told him to stop contacting her. Investigators said he responded with a threatening statement and hung up. Police later asked if she was afraid of him. She said, “Absolutely.” The stalking count ties those allegations to the fire case rather than treating them as a separate domestic dispute.
When police arrested Grundman, they said he was carrying a backpack with a loaded Ruger Security-9 handgun. His wife told investigators the weapon had been taken from the home when he left. The gun did not cause the fire, but it led to a concealed weapon charge and gave police another piece of evidence tied to the separation. The complaint also includes three counts of criminal damage to property, reflecting damage to the vehicle and other property in the garage.
Court records and local reports show the case moved through several stages in less than a month. The fire happened March 19. Grundman was arrested March 31. Formal charges were filed in early April, and bond was set at $1 million cash during his first appearance. A preliminary hearing followed, where an officer testified and the judge found enough evidence to bind the case over for trial. His arraignment was scheduled for May 5 in Outagamie County Circuit Court.
The woman has not been publicly identified in the reports reviewed for this story. Authorities also have not released a full loss estimate or a complete list of forensic test results. The known record describes a garage fire, an occupied home, alleged accelerant use, a divorce case and a defendant who police say admitted lighting gasoline but disputed the state’s claim about intent. Those facts now form the frame for the trial-level proceedings.
Grundman’s case remained pending after the bindover order. The next milestone was his May 5 arraignment, where the court was expected to set the next phase of the attempted homicide and arson prosecution.
Author note: Last updated April 28, 2026.