An Arroyo Grande man accused of slashing the throat of 26-year-old Kristen Marti and weighing her body down in a flowing Prefumo Canyon creek in January will face trial, a San Luis Obispo judge ruled following a two-day evidentiary hearing.
Robert William Koehler, 36, faces a single count of murder in the death of the San Luis Obispo woman, which investigators believe occurred Jan. 9. Koehler has pleaded not guilty and faces the possibility of life in state prison if found guilty.
Marti was last seen alive in a parked vehicle in the Prefumo Canyon area with an unidentified man on Jan. 9, and her body was discovered in a Prefumo Canyon creek bed about 50 feet from the roadway in late March following a large-scale search.
Digital Access for only $0.99
For the most comprehensive local coverage, subscribe today.
Police announced on May 16 that they arrested Koehler, who had previously been identified as a person of interest in the case, in Minneapolis, Minnesota, after a warrant was issued when he left San Luis Obispo County with his wife. He was extradited to California after being temporarily held in the Hennepin County Jail in Minnesota.
In addition to the murder charge, the district attorney’s complaint against Koehler includes a sentencing enhancement for use of a deadly weapon — a knife — during the alleged murder. The complaint also states that Koehler has a prior felony conviction for carjacking out of Shasta County in 2005.
According to witness testimony during Koehler’s preliminary hearing that began Wednesday, Marti worked as a prostitute to support a heroin and methamphetamine addiction for both herself, her boyfriend and a few others among their circle of friends.
San Luis Obispo detectives testified that Marti’s boyfriend made a missing person’s report days after Marti went to meet a man for paid sex. The boyfriend later checked on her and saw her in the parked vehicle in Prefumo Canyon, but saw from her demeanor that she “seemed OK,” one officer said.
Detectives also testified that Koehler used a complex system of cell phone anonymous messaging apps and email addresses to hide his activity with several local prostitutes and that Koehler admitted to picking up Marti the night of Jan. 9, but he told investigators she walked away after his truck broke down.
A forensic toxicologist also testified that Marti had significant amounts of alcohol, cocaine, morphine, methamphetamine, and Telazol, an animal tranquilizer normally used by veterinarians, in her system.
When testimony resumed Thursday, Det. Casey Neall said on the stand that he had searched one of Koehler’s cell phones and found internet bookmarks for sites selling Telazol.
When confronted, Neall said Koehler said he was searching on behalf of a friend who had an out-of-control pit bull, though he wouldn’t reveal the name of the friend, Neall said. Koehler denied that he bought any tranquilizers, however.
Jason Caron, a senior deputy with the Sheriff-Coroner’s Office, assisted the county’s forensic medical examiner, Dr. Joye Carter, in performing the autopsy on Marti’s body in the days following its discovery.
Caron testified Thursday that in addition to a sharp-force incision to Marti’s neck — determined to be the fatal wound — Marti also had cuts on both hands that Caron called “defensive wounds,” as if she had fought an attacker.
Caron said Carter ruled the cause of death as sharp-force injury to the neck, and that Marti likely died within minutes.
He said Marti’s body was weighed down by rocks in a shallow but flowing Perfumo Canyon creek bed for roughly 2.5 months after her death, and as such her body was very badly decomposed and small body parts such as toes were missing.
Defense attorney Trace Milan asked Caron whether the injuries seen on her body months after her death could have been caused by debris in the creek or animal activity, Caron said the neck wounds had defined edges too straight to be the result of post-death interference with her body.
Asked by Milan about the substances found in her body, Caron said Marti showed levels of the illicit drugs in her system “within the toxic range,” though that didn’t mean that the drugs killed her.
Superior Court Judge Craig van Rooyen ultimately found probable cause to move the case toward trial. Koehler is due back in court Oct. 15 for a further arraignment.
Local news matters: We rely on readers like you more than ever before, and we currently offer free access to five stories a month. Support us further with a digital subscription to help ensure we can provide strong local journalism for many years to come. #ReadLocal