Investigators say a recorded phone call, bloodstained clothing, surveillance video and an autopsy became central pieces of the homicide case.

RICHLAND TOWNSHIP, Mich. — A 36-year-old Michigan woman is charged with open murder after state police said her 50-year-old boyfriend was found dead inside a Kalamazoo County home, setting off an investigation that moved from a phone call reporting the death to an arrest, a search of the residence and an autopsy documenting 10 stab wounds.

Brittany Leigh Groat was arrested in connection with the July 24 death of Robert Walter Larsen, according to court records and reporting based on a Michigan State Police probable cause affidavit. Police said the two were in a dating relationship and that Groat had been staying at Larsen’s home for several weeks. The charge remains an allegation, and the available records do not establish that Groat has been convicted of any crime. Authorities have described the case as an apparent domestic dispute, but the publicly available reports reviewed for this story do not identify a confirmed motive or provide a full account of what happened inside the home before Larsen was killed.

The investigation began after other people contacted 911, authorities said. According to the affidavit, Groat had called someone at about 9 p.m. and said she had killed her boyfriend. Part of that call was recorded. After giving the address of the home, investigators said, Groat could be heard repeating, “I think I killed him.” Troopers were dispatched at about 9:16 p.m. to a residence on Sturtevant Avenue in Richland Township. Local reporting places the scene in the 8000 block. The people who contacted emergency dispatchers were not identified in the reports reviewed, and authorities have not publicly described their relationship to Groat or Larsen.

When troopers entered the residence, they found Larsen dead on a staircase, according to the affidavit. Investigators reported substantial blood evidence inside the home, including footprints extending through the residence and toward the garage. Those observations became part of the probable cause case, but the affidavit as reported publicly does not by itself establish who left each mark or exactly when it was made. Police obtained a search warrant before conducting a more detailed examination. Near Larsen’s body, investigators reported finding a folding knife and a baseball bat on or around the stairs and landing. No publicly available report reviewed for this story says that laboratory testing had conclusively connected either object to the fatal injuries.

Investigators also turned to surveillance video and witness interviews to establish a timeline outside the house. The affidavit says Larsen’s vehicle left the residence at about 7:11 p.m. Authorities later located the vehicle on Kings Highway with Groat alone behind the wheel. Police described her as wearing a white shirt, jean shorts and black-and-white Converse shoes and said her clothing had extensive bloodstaining. The reports do not provide a precise time for when officers stopped or located the vehicle, nor do they publicly account for every minute between the car’s departure and the approximately 9 p.m. phone call. That gap is one of several parts of the sequence that may be addressed through additional evidence as the criminal case proceeds.

After Groat was taken into custody, police said she waived her Miranda rights and spoke with investigators. According to the affidavit, she initially denied doing anything to Larsen and said she did not know how blood came to be on her clothing. She acknowledged that she and Larsen had been dating and that she had been staying at the residence. When detectives asked what occurred before she left the house, police said Groat told them she did not remember. Those statements are allegations contained in investigative records; the available reporting does not include a defense response explaining how Groat would challenge the officers’ description of the interview or the evidence collected from her clothing.

Police said Groat later gave investigators another account involving the folding knife. According to the affidavit, she said Larsen cut her with the knife as she was trying to leave and that he returned inside after she went out. She also told investigators that only she and Larsen had been inside the residence, authorities said. The publicly reported affidavit does not resolve how that statement fits with the recorded phone call, the physical evidence found in the house or the injuries later documented during the autopsy. It also does not say whether investigators photographed or medically documented an injury to Groat, whether DNA testing was completed on the knife, or whether prosecutors intend to rely on additional forensic evidence not described in the initial court filing.

The autopsy supplied investigators with a more complete account of Larsen’s injuries. Police initially reported observing at least six stab wounds after his body was moved during the search. An autopsy performed two days after the death documented 10 stab wounds along with other injuries described in the records as lacerations. The medical examiner concluded that Larsen died from blood loss caused by the stab wounds and classified the death as a homicide. A homicide ruling is a medical determination that a death resulted from another person’s actions; the criminal question of who is legally responsible and what degree of offense, if any, can be proved remains for the judicial process.

Groat was arraigned in Kalamazoo County’s 8th District Court and denied bond, according to court records cited in contemporaneous reports. She was charged with open murder, a form of charging used in Michigan when the degree of an alleged murder has not been fixed at the initial stage. Michigan case law recognizes murder as a single offense for charging purposes and allows a case to proceed without specifying first- or second-degree murder at that point. The distinction can matter greatly later. State law provides that first-degree murder carries a mandatory life sentence, while second-degree murder is punishable by life or any term of years. The filing of an open murder charge does not establish which degree, if either, prosecutors ultimately can prove.

The case began in district court because Michigan district courts handle the early stages of felony prosecutions, including arraignments, probable cause conferences and preliminary examinations. At a preliminary examination, a judge does not decide whether the accused is guilty beyond a reasonable doubt. Instead, the proceeding is used to determine whether there is probable cause to believe a felony was committed and whether there is probable cause connecting the defendant to it. If the required showing is made, the case may be bound over to circuit court for further proceedings. A defendant may also waive a preliminary examination under circumstances allowed by Michigan law.

Initial reporting said Groat was scheduled to return to court Aug. 5 for a preliminary hearing. That date has passed, but the reliable public sources reviewed for this article did not provide a verified account of the outcome of that scheduled proceeding or establish a later trial date. For that reason, no assumption is made here about whether the examination occurred, was waived or was adjourned. The confirmed posture remains that Groat was charged with open murder and denied bond after Larsen’s death, while the prosecution’s allegations, the defense’s response and the ultimate degree of any criminal liability remain matters for the courts.

The affidavit presents investigators with several forms of evidence that will have to be evaluated together rather than in isolation: the recorded phone call, the vehicle timeline, the condition of Groat’s clothing, her statements during questioning, the physical evidence collected in the home and the medical examiner’s findings. At the same time, the public record leaves important questions unanswered, including what happened immediately before the confrontation, how the knife and baseball bat were used, whether forensic testing produced additional results and how Groat’s statement that Larsen cut her will figure into her defense. Those unanswered issues are significant because an arrest affidavit is an early prosecution document, not a complete presentation of all evidence that could be introduced in court.

No reliable later report located for this article established a final disposition of the case. Groat is therefore described as accused, not convicted, and Larsen’s death remains the subject of the pending criminal prosecution reflected in the available court and police reporting. Further filings or hearings could clarify the evidence, the degree of murder prosecutors intend to pursue and any defense theory, but those developments should not be presumed before they appear in the court record.

Author note: Last updated August 29, 2026.