Grover Beach man sentenced to 56 years to life for murder

February 1, 2023

Robert Koehler


A San Luis Obispo judge sentenced a 40-year-old Grover Beach man on Tuesday to 56 years to life in prison for the 2018 murder of 26-year-old Kristen Marti.

Wielding a knife, Robert Koehler slit Marti’s throat. The San Luis Obispo woman had been missing for nearly three months when officers found her body in a creek near Perfumo Canyon in SLO.

Through computer forensics and other investigative tools, law enforcement identified Koehler as the suspect.

Following the murder, Koehler and his wife fled the Central Coast. Authorities eventually arrested the Grover Beach man in Minnesota and extradited him to SLO County.

During an eight-week trial, prosecutors introduced evidence showing that Koehler contacted Marti using secretive social media apps. He then enticed her to his location by persistently offering cocaine. A forensic medical examination revealed cocaine and tiletamine in her bloodstream. Tiletamine is a drug that causes a human body to become immobilized.

On Tuesday, Judge Jesse Marino sentenced Koehler to 56 years to life in prison, the maximum possible sentence. During the sentencing hearing, relatives of Marti, including her mother and father, described the devastation they felt as a result of Marti’s death.

“Today, we finally have justice for Kristen Marti five years after she was brutally murdered,” District Attorney Dan Dow said in a statement. “This defendant should spend the rest of his life in state prison and today’s sentence should make that possible.”